ENGINE
Contents
1. Hocker Arm Cover and Bolts af f E E 35 SmkPus S o Starter MotortoBock S A 8 Timing Gear Cover A d WwsondDamperBot 89 8 WaerPumpBak pa Note 1 Retorque after first 20 hours of operation Note 2 Retorque after first start up Index N 90 816462 2 695 ENGINES 3A 1 Tools Lubricants Sealants MERCURY MARINE SPECIAL TOOLS 91 24697 Piston Ring Expander 91 63209 Torch Lamp KENT MOORE SPECIAL TOOLS 5892 Valve Spring Compressor Head on 8062 Valve Spring Compressor Head off 23738 A 8101 Valve Guide Cleaner 8814 Valve Guide Reamer Standard 5830 02 5802 01 6880 Rocker Arm Stud Installer 5715 Stud Bore Reamer 003 in oversize 6036 8089 5910 04 24086 B 3936 03 8037 Piston Ring Compressor 5239 Connecting Rod Guide Tool 3 8 24 8087 8369 23042 B 8520 6098 01 9534 01 6978 E 5590 24420 B Valve Stem Seal Tester Valve Guide Reamer 015 in oversize Rocker Arm Stud Remover Stud Bore Reamer 013 in oversize Carbon Remover Brush Piston Support Tool Piston Pin Tool Piston Ring Groove Cleaner Cylinder Bore Checker Oil Pump Suction Pipe Installer Timing Cover Seal Aligner Cam Lobe Lift Indicator Camshaft Bearing Installer Remover Tool Distributor Shaft Lower Bearing Installer Remover Pulley Hub Puller Pulley Hub Installer Universal Torsional Damper Remover LUBRICANTS SEALANTS 92 342272. 0 eee Reassembly Dipstick Specifications All Engines Oil Pan Removal Installation 0 0 0 ee OlFPUMD S eoe eo xr KE BABES ADA AIR REOR Rn Removal Disassembly Cleaning and Inspection Reassembly Installation aaa Torsional Damper Removal Installation 0 000 cece eee eee Crankcase Front Cover Oil Seal Oil Seal Replacement Without Removing Front Cover Removal Installation Crankcase Front Cover Removal Cleaning and Inspection Installation a Flywheel and Engine Coupler Removal Inspection Installation een Rear Main Oil Seal Removal Cleaning and Inspection Installation 0 0 aaa Cleaning and Inspection Installation 0 aaa Main Bearings Inspection Checking Clearances Main Bearing Replacement Connecting Rod Bearings Inspection and Replacement Connecting Rod Piston Assembly 90 8 16462 2 695 Removal a 3A 32 Disassembly suss 3A 33 Cleaning and Inspection 3A 33 Connecting Rods 3A 33 PISLONS s scpuctac eek a3 pede dre EU ds 3A 33 Piston Pins 000 eee eee eee 3A 34 Reassembly 3A 34 Pistons and Piston Pins 3A 34 Piston Rings cece eae 3A 35 Installation 4 Aa 3A 36 Crankshaft a 3A 37 Removal ee e 3A
3. 3 Coat threads of oil seal retainer fasteners with Loctite Pipe Sealant with Teflon Install fasteners and torque to 133 Ib in 15 N m Install oil pan fasteners Torque 1 4 20 threaded fasteners to 80 Ib in 9 N m and 5 16 18 threaded fasteners to 165 Ib in 19 N m NOTE A one piece oil pan gasket may be re used if it is still pliable and is not cracked torn or otherwise damaged rr 90 816462 2 695 Main Bearings IMPORTANT Before removing main bearing caps or connecting rod caps mark them for reassemb ly in their original locations Main bearings are of the precision insert type and do not use shims for adjustment If clearances are found to be excessive a new bearing both upper and lower halves will be required Service bearings are avail able in standard size and 001 in 010 in and 020 in undersize Selective fitting of both rod and main bearing inserts is necessary in production in order to obtain close tol erances For this reason you may find one half of a standard insert with one half of a 001 in undersize insert which will decrease the clearance 0005 in from using a full standard bearing When a production crankshaft cannot be precision fitted by this method it then is ground 009 in under size on main journals only A 009 in undersize bear ing and 010 in undersize bearing may be used for precision fitting in same manner as previously de scribed Any engine fitted with a
4. in 0 03 0 1 mm does not damage plate when shaft is pressed out of gear Also support hub of gear or gear will be C seriously damaged Q 27777 T 74439 sd aaa S a Feeler Gauge b Camshaft Gear T c Camshaft Thrust Plate T d Take Measurement Here 2 N Camshaft Gear Replacement 14477 1 If inspection indicates that camshaft gear or thrust plate should be replaced remove gear from camshaft a Camshaft Gear b Support Sleeve 2 Place camshaft thru gear remover place end of c Camshaft remover on table of a press shaft out of gear Index 3A 40 ENGINES 90 816462 2 695 Installation 1 Install camshaft and gear assembly in engine block being careful not to damage camshaft bearings or camshaft co co e L ind z lt e E29 eo maba KA Aa as Z CA SF 74438 a Timing Marks b Screw Access Holes 2 Turn crankshaft and camshaft so the timing marks on gear teeth will line up Push camshaft thrust plate to block screws and torque to specifi cations 3 Check camshaft and crankshaft gear run out with a dial indicator Camshaft gear run out should not exceed 004 in 0 1 mm and crankshaft gear run out should not exceed 003 in 0 07 mm er pe Japoy m 25 p CA SF y 74440 Checking Timing Gear Run Out 4 f gear run out is excessive remove gear and clean burrs from shaft or gear must be replaced Index 90 81646
5. 3 Install torsional damper on crankshaft using tor sional damper remover and installer as follows a Install appropriate end of threaded rod into crankshaft IMPORTANT Be sure to install threaded rod in crankshaft at least 1 2 in 13 mm to prevent dam age to threads b Install plate thrust bearing washer and nut On rod 90 816462 2 695 c Install torsional damper on crankshaft by turn INSTALLATION ing nut until it bottoms out IMPORTANT Correct rotation oil seal must be used to prevent oil leak 1 Apply Quicksilver Perfect Seal to seal retainer mating surface and apply grease to seal lips 2 Install new seal with open end of seal inward us ing crankcase front cover seal installer Drive seal in until it just bottoms out Do not use excessive force 74529 a Torsional Damper Remover and Installer J 23523 E d Remove tool from crankshaft e To prevent oil leakage apply Quicksilver RTV sealant to torsional damper keyway f Install torsional damper bolt Torque to 70 lb ft 95 N m 4 Install drive pulley s Torque bolts to 35 Ib ft 48 N m 5 Install and adjust drive belts 74531 a Key In Crankshaft b Lobe of Bore Clears Key Crankcase Front Cover Oil Seal 3 Reinstall torsional damper as outlined Oil Seal Replacement Without Removing Front Cover REMOVAL 1 Remove torsional damper 2 Pry seal out of cover from the front with a large screwdriver
6. Pre ignition is abnormal fuel ignition caused by com bustion chamber hot spots Control of the start of igni tion is lost as combustion pressure rises too early causing power loss and rough running The upward motion on the piston is opposed by the pressure rise This can result in extensive damage to the internal parts from the high increase in combustion chamber temperature 72424 Pre Ignition Damage Index 3A 8 ENGINES Overlay Wiped Out Sections Lack of Oil Radius Hide Radius Ride Bright Polished Improper Seating Craters or Pockets 70436 Fatigue Failure PRE IGNITION CAUSES 1 Hot spots in the combustion chamber from glow ing deposits due in turn to the use of improper oils and or fuels 2 Overheated spark plug electrodes improper heat range or defective plug 3 Any other protuberance in the combustion cham ber such as an overhanging piece of gasket an improperly seated valve or any other inadequate ly cooled section of material which can serve as a source Engine failures which result from the foregoing con ditions are beyond the control of Mercury Marine therefore no warranty will apply to failures which oc cur under these conditions 90 816462 2 695 Detonation 7 6G Detonation commonly called fuel knock spark knock or carbon knock is abnormal combustion of the fuel which causes the fuel to explode violently The ex
7. Ensure that cooling water supply is available be fore starting the engine 9 Start engine set timing set idle speed and check for leaks Cylinder Head and Valve Conditioning Disassembly NOTE On LX models O ring seals are used only on intake valve stems 1 Using valve spring compressor compress valve spring J 8062 and remove valve locks Slowly release tool 2 Remove all valve components Index 90 816462 2 695 3 Remove valves from cylinder head and place in a rack in order for reassembly in their original lo cations 72333 a Valve Spring Compressor J 8062 Cleaning 1 Clean push rods and rocker arm assemblies Clean carbon from valves using tool J 80890 Clean gasket material from cylinder head mating surfaces 4 Clean all carbon from combustion chambers and valve ports using carbon remover brush 14274 a Carbon Remover Brush J 8089 ENGINES 3A 17 5 Thoroughly clean valve guides with valve guide cleaner J 8101 me A AS AY E O i dh i ao FA KH HO b OD uu SaaS N o e o 74286 a Valve Guide Cleaner J 8101 Inspection 1 Inspect cylinder head for cracks in exhaust ports water jackets and combustion chambers espe cially around spark plug holes and valve seats Replace heads if any cracks are found Inspect cylinder head gasket surface for burrs nicks or erosion or other damage Also check flatness of cylinder head gasket surfa
8. being careful not to distort front cov er or damage crankshaft Index LEL 90 816462 2 695 ENGINES 3A 25 Crankcase Front Cover Removal 1 Remove engine from boat if necessary to gain ac cess to cover Remove torsional damper and oil pan Remove water circulating pump Remove crankcase front cover nm e O Iw If damaged drive oil seal out of front cover from the rear using a punch Cleaning and Inspection Clean front cover in solvent and dry with compressed air Clean old gasket material and sealer from mating surfaces on cover and cylinder block Check gasket surface on front cover for distortion and true if neces sary Surfaces must be clean and flat or oil leakage may result Installation 1 Install oil seal in cover with lip of seal toward in side of engine using crankcase front cover seal installer Support cover around seal area with ap propriate tool as shown IN WG Ng E OQ p DOE NG IN LO KOY ia ST MM 74530 a Crankcase Front Cover Seal Installer J 35468 Index 3A 26 ENGINES 2 Coat both sides of front cover gasket with Quick silver Perfect Seal and place in position on en gine 3 Install front cover making sure holes in cover align with dowel pins in block Torque front cover attaching screws to 100 Ib in 11 N m Install oil pan and torsional damper as outlined Install water circulating pump Reinstall engine in boat DU O m os Fill crankcase w
9. 37 Cleaning and Inspection 3A 37 Installation Aa 3A 37 Crankshaft Sprocket 3A 38 Removal a 3A 38 Installation 4 Aa 3A 38 AP Rhes Page Camshaft uaamaunaonctaxcbadbnpe AROG 3A 38 Measuring Lobe Lift 3A 38 Removal can ma amak ba Rack p enews 3A 39 Inspection leere 3A 39 Camshaft Gear Replacement 3A 40 Installation 4 3A 41 Camshaft Bearings 3A 42 Removal 0 00 c cece eee eee 3A 42 Inspection 0 eee eee 3A 42 Installation 0 0 cee eee eee 3A 42 Cylinder Block 0 0 0 cece eens 3A 44 Cleaning and Inspection 3A 44 Cylinder Conditioning 3A 45 Cylinder Boring 3A 45 Cylinder Honing 3A 45 Piston Selection 3A 46 Oil Filter By Pass Valve 3A 46 Inspection and or Replacement 3A 46 90 816462 2 695 Torque Specifications Fastener Location Lb Ft Camshaft Sprocket Bolts 3 gt Connecting Rod Cap Nuts Cylinder Head Bolts Net Derbaor ame SSCS tol Engine Coupierto Fipwheel Ds a7 e oa Fiywheelto GrankshaBots CC 8 FonCoverBots CSCC FomMomtoBok fafa WanBemmgCapBog la 23 Cc NG Oranbo oromo oo o fef Fan Suds Sel ROI RGB E 37 OrPumpGover KA T OlPumpoBok SCS Ca NN NA ec anoa
10. cover 4 Turn crankshaft to align timing mark with cam shaft mark Remove camshaft sprocket Remove rear main seal and retainer Ensure all bearing caps main and connecting rods are marked so they can be reinstalled in their original locations 8 Remove connecting rod bearing caps then push piston and rod assemblies toward heads 9 Remove main bearing caps and carefully lift crankshaft out of cylinder block Index 90 816462 2 695 10 Remove crankshaft gear as shown 74476 11 If new main and or connecting rod bearings are to be installed remove main bearing inserts from cylinder block and bearing caps and or connect ing rod bearing inserts from connecting rod and caps Install new bearings following procedures outlined Cleaning and Inspection 1 Wash crankshaft in solvent and dry with com pressed air 2 Measure main bearing journals and crankpin di mensions with a micrometer for out of round ta per or undersize see Specifications 3 Check crankshaft for runout by supporting at front and rear main bearings journals in V blocks and check at front and rear intermediate journals with a dial indicator see Specifications 4 Replace or recondition crankshaft if not within specifications Installation 1 lfanew crankshaft is being installed remove tim ing sprocket from old crankshaft and reinstall on new crankshaft as outlined IMPORTANT Be sure that all bearings and crank sha
11. different types of equipment are available for refacing valves The recommendation of the man ufacturer of the equipment being used should be carefully followed to attain proper results EXHAUST INTAKE O 45 45 o lt E le 50695 Exhaust a 372 In 9 45 mm b 1 32 031 In 0 79 mm Min Intake C 341 In 8 16 mm d 1 32 031 In 0 79 mm Min Reassembly 1 Lubricate valve guides and valve stems with en gine oil 2 Install each valve in the port from which it was re moved or to which it was fitted 3 Install valve guide seal intake valve only over valve stem and push down until seated against head 4 Set valve spring with damper installed and cap in place 5 Place retainer on intake valve and or rotator on exhaust valve 90 816462 2 695 6 While compressing valve spring with valve spring 9 Intake Valve compressor install oil seal in lower groove of 10 Exhaust Valve valve stem making sure seal is not twisted A light coating of oil will help prevent twisting 8 Check installed height of valve springs using a narrow thin scale Measure from spring seat to top of valve spring as shown If measurement ex ceeds specified height install a valve spring shim and recheck DO NOT shim valve springs to give an installed height less than the minimum speci fied 05037 72884 a Cut Out This Portion a Valve Spring Compressor J 8062 7 Install valve lock
12. recorded from dial indicator with Specifications 9 Continue to rotate engine until indicator reads zero This will be a check on accuracy of original indicator reading 10 If camshaft readings for all lobes are within speci fications remove dial indicator assembly 11 Install rocker arm and push rod Torque nuts to 20 Ib ft 27 N m Removal Remove valve lifters as previously outlined 2 Remove crankcase front cover as previously out lined 3 Remove fuel pump Align timing gear marks then remove the two camshaft thrust plate screws by working thru holes in camshaft gear 5 Pull camshaft and gear assembly out thru front of block Index 90 816462 2 695 IMPORTANT Support camshaft carefully when removing to protect camshaft bearings 74438 a Timing Marks b Screw Access Holes Inspection 1 Measure camshaft bearing journals with a mi crometer for out of round condition If journals ex ceed 001 in 0 025 mm out of round camshaft should be replaced 2 Also check camshaft for alignment with V blocks and dial indicator which indicates exact amount camshaft is out of true If dial indicator reads more than 002 in 0 051 mm camshaft should be re placed Checking Camshaft Alignment ENGINES 3A 39 3 Inspect camshaft gear and thrust plate for wear or 44 CAUTION damage Measure camshaft end play 001 005 Position thrust plate so that woodruff key in shaft
13. remove tool and bearing from puller screw 4 Remove remaining bearings except front and rear in same manner It will be necessary to posi tion pilot in rear camshaft bearing to remove rear intermediate bearing 5 Assemble driver on driver handle and remove front and rear camshaft bearings by driving to ward center of cylinder block Index 3A 42 ENGINES Inspection Clean camshaft bearing bores in cylinder block with solvent and blow out with compressed air Be sure grooves and drilled oil passages are clean Installation 44 CAUTION Oll holes in bearings must line up with oil holes in cylinder block Oil hole is on top side of bearing shell and cannot be seen during installation so first align bearing shell oil hole with oil hole in bore and mark opposite side of bearing and block at bore to easily position oil hole during installa tion IMPORTANT Front bearing must be driven approximately 125 in 3 mm behind the block face to uncover oil hole to timing gear oil nozzle IMPORTANT All camshaft bearings are not the same Be sure to install bearings in proper loca tions Indicated by bearing manufacturer and to position bearings as follows directional refer ences are in reference to engine in its normal op erating position Lubricate outer surface of new camshaft bearings with engine oil to ease installation 1 Installing intermediate and center bearings a Install nut and thrust washer all the w
14. replace piston and piston pin assem bly Index 3A 34 ENGINES Reassembly PISTONS AND PISTON PINS IMPORTANT When reassembling pistons and connecting rods the following must be kept in mind Piston and pin are machine fitted to each oth er and must remain together as a matched set Do not intermix pistons and pins If original pistons and or connecting rods are being used be sure to assemble pistons and connecting rods so they can be reinstalled in same cylinder from which they were removed Connecting rod bearing tangs are always to ward outside of cylinder block 72368 a Rod Bearing Tangs Notch on piston must be positioned toward the front of the engine 72896 a Notch 90 816462 2 695 1 Assemble piston to connecting rod using piston 1 pin remover as shown Follow instructions supplied with kit RK KA FTV VV PARA NAKA Y SOOO KAY lj POAN ft SRK NN N E Abat NAA 72897 Slip compression ring in cylinder bore then press ring down into cylinder bore about 1 4 in 6 mm below ring travel Be sure that ring is square with cylinder wall Measure gap between ends of ring with a feeler O OS 12372 3 If gap between ends of ring is below specifica a Piston Pin Remover J 24086 B e remove OANE bind id fit m 2 Once assembled check piston for freedom of i KAMAG A TOS CSI AM NICHES movement back and forth and up and down on going l co
15. rod then turn in adjusting nut until all lash is removed This can be determined by moving push rod up and down while turning adjusting nut until all play is removed 4 Hydraulic lifters now can be adjusted by tighten ing adjustment nut an additional 3 4 turn Valve lash should be checked after engine has run and reached operating temperature Index 3A 12 ENGINES 5 Crankengine one revolution until pointer 0 mark and torsional damper mark are again in align ment This is No 4 firing position With engine in this position the following valves may be ad justed No 2 Cylinder Exhaust No 3 Cylinder Intake No 4 Cylinder Exhaust 6 Install distributor cap spark plug wires and coll lead 7 Install rocker arm cover torque to 40 lb in 4 5 N m Ca ZO Se 72300 Engine Running Following procedure should be completed only if readjustment is required 1 Run engine until it reaches normal operating tem perature then remove valve cover m With engine running at idle back off valve rocker arm nut until valve rocker arm starts to clatter 3 Turn rocker arm nut down slowly until clatter just stops This is zero lash position 4 Turn nut down 1 4 additional turn and pause 10 seconds until engine runs smoothly Repeat addi tional 1 4 turns pausing 10 seconds each time until nut has been turned down 3 4 turn from zero lash position IMPORTANT The following preload adjustment mu
16. show signs of excessive wear Inspect grooves for nicks and burrs that might cause rings to hang up Measure piston skirt across centerline of piston pin and check clearance as outlined under Cyl inder Block olip outer surface of a new top and second com pression ring into respective piston ring groove and roll ring entirely around the groove to make sure that ring is free as shown If binding occurs at any point determine cause If caused by ring groove remove by dressing with a fine cut file If binding is caused by a distorted ring recheck with another ring i mare AL NI E y NI NA m CM 4 72894 ENGINES 3A 33 Proper clearance of piston ring in its piston ring groove is very important to provide proper ring ac tion and reduce wear Therefore when fitting new rings clearances between ring and groove sur faces should be measured See Specifications o 72895 PISTON PINS 1 Piston pin clearance is designed to maintain ade quate clearance under all engine operating condi tions Because of this piston and piston pin are a matched set and not serviced separately Inspect piston pin bores and piston pins for wear Piston pin bores and piston pins must be free of varnish and scuffing when measured Measure piston pin with a micrometer and piston pin bore with a dial bore gauge or inside micrometer If clearance is in excess of the 001 in 0 025 mm wear limit
17. with light en gine oil and a clean cloth then wipe with a clean dry cloth CYLINDER BORING 1 Before using any type boring bar file off top of cyl inder block to remove dirt or burrs This is very im portant to prevent boring bar tilt with result that bored cylinder wall is not at right angles to crank shaft Measure piston to be fitted with a micrometer measuring at center of piston skirt and at right angles to piston pin Bore cylinder to same diame ter as piston and hone to give specified clear ance NOTE Hone cylinders as outlined under Cylinder Honing and Piston Selection following 3 Carefully observe instructions furnished by man ufacturer of equipment being used CYLINDER HONING 1 Follow hone manufacturer s recommendations for use of hone and cleaning and lubrication dur ing honing Occasionally during the honing operation thor oughly clean cylinder bore and check piston for correct fit in cylinder When finish honing a cylinder bore to fit a piston move hone up and down at a sufficient speed to obtain very fine uniform surface finish marks in a crosshatch pattern of approximately 30 degrees to cylinder bore Finish marks should be clean but not sharp free from imbedded particles and torn or folded metal ENGINES 3A 45 4 Permanently mark piston for cylinder to which it has been fitted and proceed to hone cylinders and fit remaining pistons IMPORTANT Handle piston
18. 009 in undersize crankshaft will be identified by the following mark ings e 009 will be stamped on crankshaft counter weight forward of center main journal e No 9 will be stamped on block at left front oil pan rail IMPORTANT If crankshaft has an undersize jour nal and a new bearing is required journal must be reconditioned to accept a 010 or 020 in under size bearing as 009 in undersize bearings are not available for service Inspection In general the lower half of the bearing except No 1 bearing shows a greater wear and the most dis tress from fatigue If upon inspection the lower half is suitable for use it can be assumed that the upper half is also satisfactory If the lower half shows evi dence of wear or damage both upper and lower halves should be replaced Never replace one half without replacing the other half Index 90 816462 2 695 Checking Clearances To obtain accurate measurements while using Plasti gage or its equivalent engine must be out of the boat and upside down so crankshaft will rest on the upper bearings and total clearance can be measured be tween lower bearing and journal To assure the proper seating of the crankshaft all bearing cap bolts should be at their specified torque In addition preparatory to checking fit of bearings the surface of the crankshaft journal and bearing should be wiped clean of oil 1 With the oil pan and oil pump removed remove bear
19. 01 0 02 Max Clearance Service Rod R Clearance 006 017 0 153 0 4318 Max CAMSHAFT Exhaust 2529 E Journal 1 8677 18697 47 440 47 490 Camshaft End Play 003 008 0 08 0 2032 Max CYLINDER HEAD 003 008in any 6 in 152 Gasket Surface Flatness or 007 0 15 Overall Max Index N 3A 4 ENGINES 90 816462 2 695 VALVE SYSTEM Pydrauic Rocker Arm Ratio 1 75 to 1 Collapsed Tappet Gap 3 4 Turn Down from Zero Lash Face Angle Seat Angle intake amp Exhaust oeat Runout Intake amp Exhaust 002 0 05 Max 1 16 0625in 1 16 mm Seat Width 1 16 5 64 0625 07812 in 1 6 2 0 mm 0010 0027 0 025 0 069 Production Stem 0007 0027 0 018 0 069 Clearance 003 0 09 Max Service 004 0 11 Max Free Length 2 1 16 in 52 mm Pressure Valve Closed 100 110 Ib 136 149 N at 1 19 32 in 41 mm Pressure Spring Valve Open 208 220 Ib 282 300 N at 1 7 32 in 31 mm Height 1 32 1 6562 42 if ternal Damper Index N 90 816462 2 695 ENGINES 3A 5 General Some of the repairs in this section must be completed with engine removed from boat Engine removal de pends upon type of repair and boat design Place en gine on repair stand for major repairs When engine removal is not required make certain that battery cables are disconnected at the battery prior to performing any on board engine repair proce dure Lubricate all moving parts during re
20. 1 Quicksilver Perfect Seal 92 825407A12 Quicksilver 2 C 4 Marine Lubricant with Teflon 92 91601 1 Quicksilver RTV Sealer Index N 3A 2 ENGINES 90 816462 2 695 Engine Specifications UNIT OF MEASUREMENT in mm LOO ae 3 0L 3 0LX Displacement 181 CID 3 0L CYLINDER BORE 0005 0 012 Max Out of Round 002 0 05 Max Thrust Side 0005 0 012 Max Production Taper Relief Side 0005 0 012 Max 001 0 02 Max PISTON CLEARANCE 0025 0035 0 064 0 088 Max 0035 0 08 Max PISTON RING COMPRESSION Production 0012 0029 0 030 0 073 Groove Clearance Em o oo SOOO Vis To 010 020 0 254 0 762 Gap SeWe 035 0 88 Max PISTON RING OIL Groove 001 006 0 026 0 152 Clearance 007 0 17 Max 010 030 0 254 0 762 Max Ga 040 1 01 Max PISTON PIN 9270 9271 23 546 23 550 0003 0006 0 008 0 01 6 Clearance Service Limit 001 0 02 Max Fit in Rod 0008 0019 0 020 0 050 Interference Index 90 816462 2 695 ENGINES 3A 3 CRANKSHAFT Diameter 2 2979 2 294 58 367 58 404 0002 0 005 Max Taper Main Journal Service 001 0 02 Max 0002 0 005 Max Out of Round Service 001 0 02 Max W No 4 001 0024 0 025 0 060 Clearance No 1 No 4 001 0025 0 03 0 06 Crankshaft End Play 002 006 0 05 0 15 Diameter 2 09980 20995 53 289 53 327 0003 0 007 Max aper Crankpin B Service 001 0 02 Max 0002 0 51 Max Out of Round Service 0
21. 2 2 695 5 Check backlash between timing gear teeth with a dial indicator Backlash should not be less than 004 in 0 010 mm or more than 006 in 0 15 74441 Checking Timing Gear Backlash 6 Install fuel pump 7 8 Install front crankcase cover Pour G M Engine Oil supplement or light engine oil over camshaft lobes and install valve lifters ENGINES 3A 41 Camshaft Bearings Removal Camshaft bearings can be replaced while engine is disassembled for overhaul or without complete disas sembly To replace bearings without complete disas sembly remove camshaft and crankshaft leaving cylinder heads attached and pistons in place Before removing crankshaft fasten connecting rods against sides of engine so that they will not interfere while re placing camshaft bearings 9 With camshaft and crankshaft removed drive camshaft rear plug from cylinder block NOTE This procedure is based on removal of bear ings from center of engine first thus requiring a mini mum amount of turns to remove all bearings 1 Using camshaft bearing remover and installer set J 6098 01 with nut and thrust washer installed to end of threads position pilot in front camshaft bearing and install puller screw through pilot 2 Install tool with shoulder toward bearing Be sure a sufficient amount of threads are engaged 3 Using two wrenches hold puller screw while turn ing nut When bearing has been pulled from bore
22. 95 72387 Measuring Cylinder Bore With Dial Indicator ti Check cylinder head gasket surfaces for warpage with a machinist s straight edge and a feeler gauge as shown Take measurements diagonal ly across surfaces both ways and straight down center If surfaces are warped more than 003 in 0 07 mm ina 6in area or 007 in 0 2 mm over all block must be resurfaced by an automotive machine shop 72910 a Machinist s Straight Edge b Feeler Gauge CYLINDER CONDITIONING 1 Performance of the following operation depends upon engine condition at time of repair If cylinder block inspection indicates that block is suitable for continued use except for out of round or tapered cylinders they can be conditioned by honing or boring Index 90 816462 2 695 If cylinders have less than 005 in 0 127 mm ta per or wear they can be conditioned with a hone and fitted with high limit standard size piston A cylinder bore of more than 005 in wear or taper may not clean up entirely when fitted to a high limit piston To entirely clean up the bore it will be nec essary to bore for an oversize piston If more than 005 in taper or wear bore and hone to smallest oversize that will permit complete resurfacing of all cylinders When pistons are being fitted and honing is not necessary cylinder bores may be cleaned with a hot water and detergent wash After cleaning swab cylinder bores several times
23. ENGINE 181 CID 3 0L 4 CYLINDER GM ENGINE Index Table of Contents Torque Specifications Tools Lubricants Sealants Engine Specifications Cylinder Bore Piston Clearance Piston Ring Compression Piston Ring Oil SIS POLT Ul rosse e Ei eus 8909 8 ROC RO dos Crankshaft Camshaft Cylinder Head Valve System General Engine Identification Engine Rotation Firing Order 000 c cece eee Priming Engine With Oil Tool Required Bearing Failures Piston Failures 0 0 0 0 cece eee Pre Ignition Pre Ignition Causes Detonation cece eee Other Causes of Detonation Engine Mounts 000 cece e eee Rocker Arm Cover 20000 eee Removal Installation a Rocker Arm Push Rod Removal Cleaning and Inspection Installation Em Valve Adjustment 00000ee Engine Not Running Engine Running Hydraulic Valve Lifters Locating Noisy Lifters Removal Cleaning and Inspection Installation a Valve Stem Oil Seal Valve Spring Replacement Oil Seal Head Installed Cylinder Head Cleaning and Inspection Installation M Cylinder Head and Valve Conditioning Disassembly Index 3A ENGINES 3A 11 3A 11 3A 11 3A 11 Cleaning Inspection Rocker Arm Studs Valve Guide Bore Repair Valve Springs Checking Tension Valve Seats
24. aft first rearward then for ward with a lead hammer This will line up rear main bearing and crankshaft thrust surfaces Torque rear main bearing cap to 75 Ib ft 102 N m Connecting Rod Bearings Connecting rod bearings are of the precision insert type and do not use shims for adjustment DO NOT FILE RODS OR ROD CAPS If clearances are found to be excessive a new bearing will be required Ser vice bearings are available in standard size and 001 in and 002 in undersize for use with new and used standard size crankshafts and in 010 in and 020 in undersize for use with reconditioned crankshafts On removing a connecting rod cap it is possible to find a 010 in undersize bearing These are used in manufacturing for selective fitting 90 816462 2 695 Inspection and Replacement IMPORTANT Before you remove the connecting rod cap mark the side of the rod and cap with the cylinder number to assure matched reassembly of rod and cap Remove connecting rod cap and bearing 2 Inspect bearing for evidence of wear or damage Defective bearings should not be installed Typi cal bearing failures are shown under General 3 Wipe bearings and crankshaft clean of oil Measure crankpin for out of round of taper with a micrometer If not within specifications replace or recondition crankshaft If within specifications and new bearing is to be installed measure maxi mum diameter of crankpin to determine new bearing
25. all used valve lifters if a new camshaft has been installed 1 Install valve lifters into bores 2 Install push rod covers using new gaskets and torque to specification 3 Install distributor positioning rotor to number 1 cylinder position then connect primary lead at coil Install distributor cap and spark plug wires Adjust valves to specifications Adjust ignition timing carburetor idle speed and mixture 90 816462 2 695 Valve Stem Oil Seal Valve Spring OT DD oro 2o 50841 Keys 2 per Valve Cap Seal On LX Models These Are Used Only On Intake Valve Stems Do Not Install Them On Exhaust Valve Stems Valve Spring Shield Valve Spring Damper Internal Valve Index 90 816462 2 695 Replacement Oil Seal Head Installed 1 2 Remove rocker arm cover Remove spark plug rocker arm and push rod on cylinder to be serviced Place piston for that cylinder at TDC to prevent valves from dropping into the cylinder Compress valve spring with tool J 5892 and re move valve keys valve spring cap spring shield and valve spring 72881 a Valve Spring Compressor J 5892 b Rocker Arm Nut o Remove valve stem oil seal a Valve Guide Seal 6 To install set valve spring close coiled end of spring is installed against cylinder head valve shield and valve cap in place Compress spring with tool J 5892 and install oil seal in lower groove of ste
26. apers toward the middle or ends there is a difference in clearance indi cating taper low spot or other irregularity of the bear ing or journal Be sure to measure the journal with a micrometer if the flattened gauging plastic indicates more than 001 in difference 6 If the bearing clearance is within specifications the bearing insert is satisfactory If the clearance is not within specifications replace the insert Al ways replace both upper and lower inserts as a unit 7 A standard or 001 in undersize bearing may produce the proper clearance If not it will be nec essary to regrind the crankshaft journal for use with the next undersize bearing 8 After selecting new bearing recheck clearance Index 3A 30 ENGINES 9 Proceed to the next bearing After all bearings have been checked rotate the crankshaft to see that there is no excessive drag When checking No 1 main bearing loosen accessory drive belts so as to prevent tapered reading with plastic gauge Main Bearing Replacement 1 Remove and inspect crankshaft 2 Remove main bearings from cylinder block and main bearing caps 3 Coat bearing surfaces of new correct size main bearing with oil and install in cylinder block and main bearing caps Check clearance Install crankshaft 5 Torque all main bearing caps EXCEPT THE REAR MAIN CAP to 75 Ib ft 102 N m Torque rear main bearing cap to 10 12 Ib ft 14 16 N m then tap end of cranksh
27. assembly with engine oil Apply Quicksilver Perfect Seal on threads of and under heads of cylinder head bolts and on threads of all cylinder block external bolts screws and studs No of Cu In Litres Cylinders Displacement MCM 3 0L 3 0LX 181 3L Engine Identification The MerCruiser Model can be determined by looking at the LAST TWO LETTERS of the engine code stamped into the cylinder block This code number is stamped on all MerCruiser power packages and re placement partial engines but not replacement cylin der block assemblies If the engine serial number and or model decals are missing the engine code letters may help in deter mining the engine models CD LE A S lt t 7 7 ac Za uu E C TRS mili e y CSA KOY SANA S A t E mGa faf 4 7 Nt rs 74520 3 0L uses the 2 5L cylinder head 3 0LX uses the 3 0L cylinder head a 4 Cylinder In Line Engine Code Next To Distributor G M Engine Code Location MCM Stern Drive Engines LH Rotation 3 0L RM RJ 3 0LX RN RK Index 3A 6 ENGINES Engine Rotation Engine rotation terminology at times has caused con fusion To clarify engine rotation is determined by ob serving flywheel rotation from the rear transmission or stern drive end of the engine looking forward wa ter pump end PROPELLER ROTATION IS NOT NECESSARILY THE SAME as engine rotation Do not rely on propel ler rotation in determining engine rotation 72001 a L
28. ay onto puller screw then position pilot in front cam shaft bearing bore and insert screw through pilot 90 816462 2 695 b Index center camshaft bearing then position appropriate size remover and installer tool in bearing and thread puller screw into tool Be sure atleast 1 2 in 13 mm of threads are en gaged ERES S 74478 Pulling Cam Bearing From Bore c Using two wrenches hold puller screw and turn nut until bearing has been pulled into po sition Remove the remover and installer tool and check to ensure that oil hole s in bearing are positioned correctly d Install intermediate bearings in same manner being sure to index bearings correctly It will be necessary to position pilot in rear camshaft bearing bore to install rear intermediate bear ing Index 90 816462 2 695 2 Installing front and rear bearings a Install appropriate size remover and installer tool on drive handle b Index front bearing as explained in Impor tant above and drive it into position with tool Check position of oil hole s in bearing to ensure bearing is positioned correctly a Y ire A JY UNG O o dq ut 74479 Removal And Installation Camshaft Bearings a Installation Tool b Camshaft Bearing c Install rear bearing in same manner being sure to index bearing correctly 3 Install a new camshaft rear plug IMPORTANT Plug must be installed flush to 1 32 in 0 8 mm deep and must be
29. b in 9 N m and 5 16 18 threaded fasteners to 165 lb in 19 N m Install dipstick tube and dipstick Fill crankcase with required quantity of oil of spe cified viscosity See Section 1B Maintenance Oil Pump The oil pump consists of two gears and a pressure regulator valve enclosed in a two piece housing Oil pump is driven by distributor shaft which is driven by a helical gear on camshaft Removal 1 Remove oil pan as previously outlined 2 Remove gasket carefully as the one piece gasket for the oil pan may be reused if still pliable and not cracked torn etc 3 Remove oil pump Disassembly 1 Remove pump cover IMPORTANT Mark gear teeth for reassembly with same teeth indexing 2 Remove idler gear and drive gear from pump body 3 Remove retaining pin spring and pressure regu lator valve from pump cover IMPORTANT Do not remove pickup screen and pipe assembly unless replacement is necessary Loss of press fit condition could result in an air leak and loss of oil pressure IMPORTANT Do not disturb pickup screen on pipe This is serviced as an assembly Index 90 816462 2 695 4 f pickup screen and pipe assembly requires re placement mount pump in a soft jawed vise and extract pipe from pump Cleaning and Inspection 1 Wash all parts in cleaning solvent and dry with compressed air 2 Inspect pump body and cover for cracks or exces sive wear 3 Inspect pump gears for dama
30. ce using a machinist s straight edge and feeler gauges as shown Refer to Specifications O o 2885 Straight Edge Feeler Gauge Jake Measurements Diagonally Across Head Both Ways and Straight Down Center Head Index 3A 18 ENGINES IMPORTANT Cylinder head to block gasket sur face should be resurfaced if warped more than specified When head resurfacing is required cylinder head to intake manifold gasket surface on head must be milled to provide proper align ment between intake manifold and head 3 Inspect valves for burned heads cracked faces or damaged stems IMPORTANT Excessive valve stem to bore clear ance will cause excessive oil consumption and possible valve breakage Insufficient clearance will result in noisy and sticky valves 4 Measure valve stem clearance as follows a b C a Attach a dial indicator to cylinder head posi tioning it against the valve stem and close to the valve guide b Holding valve head off seat about 1 16 in 2 mm move valve stem back and forth in direc tion shown Compare stem clearance with specifications c If clearance exceeds specifications it will be necessary to ream valve guides for oversized valves as outlined under Valve Guide Bore Repair my ad 4 Sy j a y IS x D p MA CN fj a 72336 Valve Stem Dial Indicator Valve Guide 90 816462 2 695 Rocker Arm Studs Rocker arm studs with damaged threads or
31. e must be reconditioned measure new piston diameter across centerline of piston pin then hone cylinder bore to correct clearance preferable range 4 Mark piston to identify cylinder for which it was fitted Oil Filter By Pass Valve Inspection and or Replacement With oil filter removed check spring and fiber valve for operation Inspect for a cracked or broken valve If replacement is necessary pry valve out with screw driver Install and seat a new valve by tapping in place with a 9 16 in thin wall deep socket 90 816462 2 695
32. e ventilation hoses 2 Remove any items that interfere with the removal of rocker arm covers IMPORTANT DO NOT pry rocker arm cover loose Gaskets which may adhere to cylinder head and rocker arm cover may be loosened by bumping end of rocker cover from the rear with palm of hand or a rubber mallet 3 Hemove rocker arm cover Installation 1 Clean sealing surfaces on cylinder head and rocker arm cover with degreaser 2 Place new rocker arm cover gasket in position in rocker arm cover 3 Install rocker arm cover Torque screws to 40 lb in 4 5 N m 4 Install exhaust manifolds if removed Install any items which were removed to allow re moval of rocker arm covers 6 Connect crankcase ventilation hoses to rocker arm covers 90 816462 2 695 Rocker Arm Push IMPORTANT Place rocker arm assemblies and push rods in a rack for reassembly in their origi Rod nal locations o gt O 3 gt Cleaning and Inspection 1 Clean parts with solvent and dry with compressed o II air 2 Inspect all contact surfaces for wear Replace all damaged parts Q Installation d IMPORTANT When installing rocker arms and rocker arm balls coat bearing surfaces of rocker arms and rocker arm balls with engine oil 1 Install push rods in their original locations Be 74287 sure push rods seat in lifter socket Valve Mechanism 2 Install rocker arms rocker arm balls and rocker a Nut arm nuts in their original loca
33. eft Hand Rotation CCW All Stern Drive Engines Firing Order 1 3 4 2 90 816462 2 695 Priming Engine With Oil IMPORTANT This applies to all power packages that have not been run within 6 months replace ment of partial engines or after rebuilding an en gine Tool Required 91 52024A1 Remote Starter Kit Index 90 816462 2 695 71089 Fill crankcase to proper level with the recom mended engine oil Remove spark plugs Leave ignition key in OFF position Connect remote starter switch 91 52024A1 to large 12 V terminal RED battery cable and small terminal RED Y ELLOW wire on starter motor a lf remote starter switch is not available dis connect PURPLE wire from ignition coil be fore using key switch to crank the engine over Tape terminal on PURPLE wire to prevent it from touching ground Crank engine for 15 seconds then allow starter motor to cool down for 1 minute This should pre vent starter motor from overheating Repeat this process until a total of 45 seconds of cranking time is achieved Remove remote starter switch a If key switch was used reconnect PURPLE wire to ignition coil Install spark plugs and wires Supply cooling water to seawater pump and start motor ENGINES 3A 7 Bearing Failures Dirt Imbedded Scratched nto Bearing by Dirt Material Scratches Overlay Gone from Entire Surface Tapered Journal Piston Failures Pre Ignition
34. ft 2 Tighten oil pump bolt to 65 Ib ft 88 N m Install oil pan as outlined The one piece gasket for the oil pan may be reused if still pliable and not cracked torn etc Torsional Damper Removal 1 Support front of engine if in boat with overhead hoist 2 Remove front mounting bracket and drive belt Remove retaining bolt if so equipped 3 Install tool J 6978 E to balancer and turn puller Remove drive pulley then remove torsional damper retaining bolt IMPORTANT DO NOT use a universal claw type puller to remove torsional damper in next step as outside ring of torsional damper is bonded in rubber to the hub and use of claw type puller may break the bond Index 3A 24 ENGINES 4 Remove torsional damper with torsional damper remover and installer 72890 a Torsional Damper Remover and Installer J 6978 E Installation IMPORTANT The inertia weight section of tor sional damper is assembled to the hub with a rub ber type material The installation procedure with proper tool must be followed or movement of the inertia weight on the hub will destroy the tuning of the torsional damper 1 Replace key in crankshaft if it is damaged 2 Coatseal surface of torsional damper with engine oil NOTE If a suitable torsional damper installer installa tion tool is not available use a block of wood as a driv er Be very careful not to cause pulley or weight to shift on their rubber mounts
35. ft journals are clean ENGINES 3A 37 2 Install main bearings in engine block as shown 72359 a Lower Bearing Insert b Upper Bearing Insert c Oil Groove Main Bearing Inserts 1 Carefully lower crankshaft into place Be careful not to damage bearing surface 2 Check clearance of each main bearing following procedure outlined under Main Bearings If bearing clearances are satisfactory apply engine oil to journals and bearings 3 Install main bearing caps Torque bolts to 75 Ib ft 102 N m When tightening rear main bearing cap follow procedure outlined under Main Bear ings Check crankshaft end play as previously outlined Install rear main seal retainer and seal Torque fasteners to 133 Ib in 15 N m 6 Check clearance for each connecting rod bear ing following procedure under Connecting Rod Bearings If bearing clearances are satisfactory apply engine oil to journals and bearings 7 Install rod caps and torque nuts to 45 Ib ft 61 N m 8 Turn crankshaft so mark on timing sprocket is fac ing camshaft 9 Install as outlined a Timing chain and sprocket on camshaft align marks with crankshaft Timing chain cover Oil pump Dipstick tube and oil pan Spark plugs mog no 5 Torsional damper and crankshaft pulley Water pump Belts i Flywheel and drive coupler gt Index 3A 38 ENGINES j Flywheel housing k Starter 10 Install new o
36. ge and excessive wear Check for loose drive gear shaft in pump body Inspect inside of pump cover for wear that would permit oil to leak past ends of gears IMPORTANT Pump gears and body are not serv iced separately If pump gears or body are dam aged or worn replacement of entire oil pump as sembly is necessary 6 Inspect pickup screen and pipe assembly for damage to screen and pipe 7 Check pressure regulator valve for fit Reassembly 44 CAUTION Be careful of twisting shearing or collapsing pipe while installing in pump Pickup screen must be parallel to oil pan bottom when oil pump is in stalled If pickup screen and pipe assembly was removed mount pump in a soft jawed vise apply Quicksilver Perfect Seal to end of new pipe and using oil pump suction pipe installer J 21882 tap the pipe in place with a hammer IMPORTANT Oil internal parts liberally before in stallation 1 Install pressure regulator valve and related parts Install drive gear in pump body Install idler gear in pump body with smooth side of gear toward pump cover opening gn marks made in disassembly 4 Fill gear cavity with engine oil ENGINES 3A 23 5 Install pump cover and torque attaching bolts to 80 Ib in 9 N m 6 Turn extension shaft by hand to check for smooth operation Installation 1 Install pump with extension shaft to rear main bearing aligning extension shaft with distributor drive sha
37. il filter Fill crankcase with oil Crankshaft Sprocket Removal 1 Remove torsional damper and crankcase front cover as previously outlined 2 Remove camshaft timing chain as outlined and using crankshaft gear and sprocket puller J 5825 A remove crankshaft sprocket Installation 1 Using crankshaft gear and sprocket installer as shown install sorocket on crankshaft 72377 a Crankshaft Gear and Sprocket Installer J 5590 2 Install timing chain as outlined 3 Install crankcase cover and torsional damper as outlined Camshaft Measuring Lobe Lift NOTE Procedure is similar to checking valve timing If improper valve operation is indicated measure lift of each push rod in consecutive order and record readings 90 816462 2 695 4 Remove valve mechanism as previously out lined 5 Position indicator with ball socket adaptor tool on push rod Be sure that push rod is in lifter socket ENG o IL BM eas Ea MU w ES ul W f Gn A NW el 3 i i Gi fh i N 12907 a Ball Socket Adaptor Tool J 8520 1 6 Rotate crankshaft torsional damper slowly in di rection of rotation until lifter is on heel of cam lobe At this point push rod will be in its lowest position 7 Set dial indicator on zero then rotate balancer slowly or attach an auxiliary starter switch and bump engine over until push rod is in fully raised position 8 Compare total lift
38. ing cap and wipe oil from journal and bearing cap to be inspected 2 Place a piece of gauging plastic the full width of the bearing parallel to the crankshaft on the jour nal as shown a Gauging Plastic b Journal 3 Install the bearing cap and evenly torque the re taining bolts to specifications Bearing cap MUST be torqued to specification in order to assure proper reading Variations in torque affect the compression of the plastic gauge IMPORTANT Do not rotate the crankshaft while the gauging plastic is between the bearing and journal 4 Remove bearing cap The flattened gauging plas tic will be found adhering to either the bearing cap or journal ENGINES 3A 29 5 Onthe edge of the gauging plastic envelope there is a graduated scale which is correlated in thou sandths of an inch Without removing the gauging plastic measure its compressed width at the widest point with the graduations on the gauging plastic envelope as shown a Compressed Gauging Plastic b Graduated Scale NOTE Normally main bearing journals wear evenly and are not out of round However if a bearing is be ing fitted to an out of round journal 001 in max be sure to fit to the maximum diameter of the journal If the bearing is fitted to the minimum diameter and the journal is out of round 001 in interference between the bearing and journal will result in rapid bearing fail ure If the flattened gauging plastic t
39. ing ring expander ENGINES 3A 35 f Install top compression ring with marked side up using ring expander Installation IMPORTANT Cylinder bores must be clean be fore piston installation Clean with a light honing as necessary Then clean with hot water and de tergent wash After cleaning swab bores several times with light engine oil and clean cloth then wipe with a clean dry cloth 1 Lubricate connecting rod bearings and install in rods and rod caps 2 Lightly coat pistons rings and cylinder walls with light engine oil 3 With bearing caps removed install connecting rod bolt guide 3 8 24 J 5239 on connecting rod bolts IMPORTANT Be sure ring gaps are properly posi tioned as shown ENGINE FRONT ENGINE RIGHT ENGINE LEFT A Oil Ring Spacer Gap Tang in Hole or Slot within Arc B Oil Ring Rail Gaps C 2nd Compression Ring Gap D Top Compression Ring Gap Ring Gap Location Index 3A 36 ENGINES 4 Install each connecting rod and piston assembly in its respective bore Install with connecting rod bearing tangs toward outside of cylinder block Use piston ring compressor to compress rings Guide connecting rod into place on crankshaft journal with connecting rod bolt guide Use a hammer handle with light blows to install piston into bore Hold ring compressor firmly against cyl inder block until all piston rings have entered cyl inder bore IMPORTANT Be sure to install new p
40. istons in same cylinders for which they were fitted and used pistons in same cylinder from which they were removed Each connecting rod and bearing cap should be marked beginning at front of en gine Numbers on connecting rod and bearing cap must be on same side when installed in cylin der bore If a connecting rod is ever transposed from one block or cylinder to another new bear ings should be fitted and connecting rod should be numbered to correspond with new cylinder number d 72898 a Piston Ring Compressor J 8037 Remove connecting rod bolt guide Install bearing caps and torque nuts to 20 lb ft 27 N m then tighten nuts an additional 60 de grees angular torque using a Torque Angle Gauge 7 Check connecting rod side clearance as pre viously described NOTE If bearing replacement is required refer to Connecting Rod Bearings 90 816462 2 695 8 Install as previously outlined a Oil pump b Dipstick and oil pan c Cylinder heads d Intake manifold e Distributor 9 Fill crankcase with oil Refer to SECTION 1 Maintenance 10 Torque rocker arm nuts to 20 lb ft 27 N m Crankshaft Removal Remove engine from boat Drain crankcase oll Remove as outlined Starter Flywheel housing Drive coupler and flywheel Belts Water pump mog oo p Crankshaft pulley and torsional damper Spark plugs gt Oil pan and dipstick tube i Oil pump j Timing chain
41. ith engine oil 44 CAUTION Ensure that cooling water supply is available be fore starting the engine 8 Start engine and check for water and oil leaks Flywheel and Engine Coupler Removal 1 Remove engine from boat Refer to SECTION 2 Hemoval and Installation 2 Refer to Flywheel Housing description in this section and remove flywheel housing and related parts 72318 a Flywheel Housing b Cover c Press Mount Out with Press 90 816462 2 695 3 Remove MOM coupler 4 Remove flywheel 72349 Alpha One Coupler Inspection 1 Inspect splines in coupler for wear 2 Check flywheel ring gear for worn and missing teeth Installation 1 Clean mating surfaces of flywheel and crank shaft Remove any burrs Mating surfaces must be clean bare metal 2 Aligning dowel hole in flywheel with dowel in crankshaft install flywheel Torque bolts to 75 Ib ft 100 N m 3 Check flywheel runout as follows a Attach a dial indicator to engine block b Take readings around outer edge of flywheel Push in on flywheel to remove crankshaft end play Index 90 816462 2 695 c Maximum runout 008 in 0 203 mm a 008 in 0 203 mm Max Runout b Push Flywheel and Crankshaft Forward as Far as It Will Go when Taking Reading 4 Insert three rubber bumpers in Alpha coupler be fore installation on flywheel 72354 a Rubber Bumper 5 Install drive coupler Torque bol
42. k NOTE It will be necessary to turn crankshaft slightly to disconnect and remove some connecting rod and piston assemblies 12892 a Connecting Rod Bolt Guide 3 8 24 J 5239 90 816462 2 695 Disassembly 1 Disassemble piston from connecting rod using piston pin remover as shown Piston Pin Remover J 24086 B Arched Base Piston Connecting Rod Rod Support N 0oooocnm Position connecting rod on tool rod support with rod support inserted between connecting rod end and piston Align piston pin with hole located in top of arched base 3 Insert pin remover thru hole located in top of arched base and into piston pin hole Press on pin remover to remove piston pin Cleaning and Inspection CONNECTING RODS 4 Washconnecting rods in cleaning solvent and dry with compressed air 5 Check for twisted and bent rods and inspect for nicks and cracks Replace damaged connecting rods Index 90 816462 2 695 PISTONS NOTE Cylinder bore and taper must be within speci fications before pistons can be considered for re use 1 Clean varnish from piston skirts with a cleaning solvent DO NOT WIRE BRUSH ANY PART OF PISTON Clean ring grooves with a groove clean er and make sure oil ring holes are clean Inspect piston for cracked ring lands skirts and pin bosses wavy worn ring lands scuffed or dam aged skirts and eroded areas at top of piston Re place pistons which are damaged or
43. m making sure that seal is flat and not twisted ENGINES 3A 15 NOTE A light coat of oil on seal will help prevent twisting when compressor tool is released IMPORTANT Do not turn crankshaft while valve springs retainers and locks are removed or valves will fall into cylinder 7 Install valve keys and release compressor tool Be sure that keys seat properly in upper groove of valve stem Install push rods and rocker arm assemblies 9 Torque rocker arm nuts to 20 lb ft 27 N m 10 Install rocker arm cover and torque to 40 lb in 4 5 N m Install spark plug and torque to 15 Ib ft 20 N m 11 Install spark plug and torque to specifications 12 Repeat steps 2 thru 8 for other cylinders Cylinder Head Cylinder Head Torque Sequence 1 Drain engine cooling system 2 Remove as outlined a Exhaust manifolds b Intake manifold c Rocker arm covers d Rocker arm assemblies and push rods keep in order for reassembly in their original loca tions e Any components attached to front or rear of cylinder head f Spark plugs g Head bolts Index 3A 16 ENGINES 44 CAUTION The head gasket may be holding cylinder head to block Use care when prying off cylinder heads DO NOT damage gasket surfaces DO NOT drop cylinder heads 3 Place cylinder head on wooden blocks to prevent damage to gasket surfaces Cleaning and Inspection 1 Clean gasket material and sealer from engine bl
44. me ENGINES 3A 13 3 Make matching marks on all retainers and lifters as to location and orientation in bores to allow reassembly in exact position on camshaft lobes so that the roller s bearing and roller will roll in the same direction on the same lobe if reused Re move valve lifters 05030 LIFTER A LIFTER B 05030 LIFTER A LIFTER B Push Rod Seat Retainer Lifter Body Push Rod Seat Metering Valve Lifter A Inertia Valve Lifter B Plunger Check Ball Check Ball Spring Check Ball Retainer Plunger Spring QOO Oo SG gt o Index 3A 14 ENGINES Cleaning and Inspection 1 Thoroughly clean all parts in cleaning solvent and inspect them carefully 2 If any parts are damaged or worn entire lifter as sembly should be replaced 3 Tf outer lifter body wall is scuffed or worn inspect cylinder block lifter bore 4 f push rod seat is scuffed or worn inspect push rod Installation IMPORTANT It is recommended that the engine oil be changed and a new oil filter be installed whenever servicing valve lifters or camshaft IMPORTANT Before installing lifters coat the lift er with engine oil If new lifters or a new camshaft have been installed an additive containing EP lube such as General Motors Cam and Lifter Pre lube or equivalent should be poured over cam shaft lobes before installing lifters IMPORTANT DO NOT inst
45. new correct size bearing and measure the clear ance Be sure to check what size bearing is being re moved in order to determine proper replacement size bearing If clearance cannot be brought to within specifications the crankpin will have to be ground undersize If the crankpin is already at maximum undersize replace crankshaft Coat the bearing surface with oil install the rod cap and torque nuts to 45 Ib ft 61 N m When all connecting rod bearings have been in stalled tap each rod lightly parallel to the crank pin to make sure they have clearance Measure all connecting rod side clearances be tween connecting rod caps as shown 006 014 0 152 0 356 MI iy X 72891 a Take Measurement Here Index 3A 32 ENGINES Connecting Rod Piston Assembly Removal 1 With oil pan oil pump and cylinder head removed use a ridge reamer to remove any ridge and or deposits from upper end of cylinder bore IMPORTANT Before ridge and or deposits are re moved turn crankshaft until piston is at bottom of stroke and place a cloth on top of piston to col lect cuttings After ridge and or deposits are re moved turn crankshaft until piston is at top of stroke then remove cloth and cuttings 2 Inspect and mark connecting rods and bearing caps Remove connecting rod cap and install connect ing rod bolt guide 3 8 24 on bolts Push connect ing rod and piston assembly out of top of cylinder bloc
46. nnecting rod Piston should move freely in all Clean and inspect pistons if not previously done directions IF it does not piston pin bore is tight Install piston rings as follows and piston pin assembly must be replaced na 3 Ifa new connecting rod has been installed mark Hee dpi e e AMN SGEE AN connecting rod and cap on side of rod and cap with slots for connecting rod bearing tangs with b Hold spacer ends butted and install lower cylinder number in which it will be installed steel oil ring rail with gap properly located c Install upper steel oil ring rail with gap proper All compression rings are marked on upper side of d Flexthe oil ring assembly to make sure ring is ring When installing compression rings make sure free If binding occurs at any point the cause that marked side IS toward top of piston The top ring should be determined and If caused by ring IS treated with molybdenum for maximum life Oil con groove removed by dressing groove with a trol rings are a three piece type consisting of 2 seg fine cut file If binding is caused by a distorted ments rails and a Spacer ring use a new ring Oil control rings are a three piece type consisting of two rings and a spacer IMPORTANT Use piston ring expander 4 Select rings comparable in size to cylinder bore and piston size Index 90 816462 2 695 91 24697 for compression ring installation e Install lower compression ring with marked side up us
47. ock and cylinder heads 2 Inspect sealing surfaces for deep nicks and scratches Inspect for corrosion around cooling passages Clean head bolt threads and engine block bolt hole threads making sure no dirt old oil or cool ant remain Installation 44 CAUTION When using ribbed stainless steel head gaskets apply a thin coating of Quicksilver Perfect Seal to both sides of gasket Too much sealer may hold gasket away from head or block causing leakage DO NOT use sealer on graphite composition head gaskets 1 Place head gasket in position over dowel pins 2 Carefully set cylinder head in place over dowel pins 3 Coat threads of head bolts with Quicksilver Per fect Seal and install finger tight 4 To insure gasket sealing torque head bolts in torque sequence to 90 lb ft 122 N m 5 Install push rods rocker arm assemblies and lift er restrictors in their original positions 6 Torque rocker arm nuts to 20 lb ft 27 N m 90 816462 1197 7 Install as outlined a Intake manifold Rocker arm covers Exhaust manifolds Spark plugs non o Any components removed from front or rear of cylinder heads 8 Follow procedures in SECTION 6A or 6B of this manual Seawater Cooled Models Provide for adequate water supply to seawater pickup see SECTION 6A Closed Cooled Models Refill closed cooling section see SECTION 6B and provide ade quate water supply to seawater pickup A CAUTION
48. p between plunger and bore of lifter body usually caused by an abrasive piece of dirt or metal wedged between plung er and lifter body 2 Moderate rapping noise probable causes are a Excessively high leakdown rate b Leaky check valve seat c Improper adjustment Index 90 816462 2 695 3 General noise throughout valve train this will in most cases be a definite indication of insufficient oil supply or improper adjustment 4 ntermittent clicking probable causes are a A microscopic piece of dirt momentarily caught between ball seat and check valve ball b In rare cases ball itself may be out of round or have a flat spot c Improper adjustment In most cases where noise exists in one or more lift ers all lifter units should be removed disassembled cleaned in solvent reassembled and reinstalled in engine If dirt corrosion carbon etc is shown to ex ist in one unit it more likely exists in all the units thus it would only be a matter of time before all lifters caused trouble Removal 1 Remove as previously outlined a Rocker arm covers b Intake manifold IMPORTANT Keep valve push rod and hydraulic lifter from each valve together as a matched set and mark or store them so they can be reinstalled in the same location later c Rocker arm assemblies and push rods 2 Remove fasteners from lifter retainers restric tors and remove retainers Do not disturb lifters at this ti
49. parallel with rear surface of cylinder block 4 Install crankshaft and camshaft as previously out lined ENGINES 3A 43 Cylinder Block Cleaning and Inspection 1 4 Remove all engine components as previously outlined Wash cylinder block thoroughly in cleaning sol vent and clean all gasket surfaces Remove oil gallery plugs and clean all oil pas sages Remove expansion plugs NOTE These plugs may be removed with a sharp punch or they may be drilled and pried out o Clean and inspect water passages in cylinder block Inspect cylinder block for cracks in cylinder walls water jacket valve lifter bores and main bearing webs 44 CAUTION Measure cylinder walls for taper out of round or excessive ridge at top of ring travel This should be done with a dial indicator or inside micrometer Carefully work gauge up and down cylinder to de termine taper and turn it to different points around cylinder wall to determine out of round condition If cylinders exceed specifications bor ing and or honing will be necessary Index 3A 44 ENGINES 72 A 385 A At right angle to centerline of engine B Parallel to centerline of engine Out of Round Difference between A and B Taper Difference between measurement A at top of cylin der bore and A measurement at bottom of cylinder bore Cylinder Measurement 72386 Measuring Cylinder Bore With Snap Gauge 90 816462 2 6
50. plosion in turn causes overheating or dam age to the spark plugs pistons valves and in severe cases results in pre ignition Use of low octane gasoline is one of the most com mon causes of detonation Even with high octane gasoline detonation could occur if engine mainte nance is neglected OTHER CAUSES OF DETONATION IMPORTANT Use of improper fuels will cause en gine damage and poor performance 1 Over advanced ignition timing 2 Lean fuel mixture at or near full throttle could be caused by carburetor or leaking intake manifold 3 Cross firing spark plugs Spark occurs Index 90 816462 2 695 combustion begins 4 Excessaccumulation of deposits on piston and or combustion chamber results in higher compres sion ratio 5 Inadequate cooling of engine by deterioration of cooling system Engine failures which result from the foregoing con ditions are beyond the control of MerCruiser there fore no warranty will apply to failures which occur un der these conditions 72425 Detonation Damage continues detonation 72315 ENGINES 3A 9 Engine Mounts 74275 Front Mount Press Mount Out with Press 72318 Rear Mount Flywheel Housing Index 3A 10 ENGINES Rocker Arm Cover Removal It may be necessary to remove exhaust manifold be fore removing rocker arm cover Refer to Section 7B for removal 1 Disconnect crankcas
51. s grease may be used to hold them in place and slowly release tool making sure locks seat properly in upper grooves of valve stem CD a Valve Spring Installed Height Checking Valve Spring Installed Height 12882 1 Valve Locks 2 Retainer 3 Rotator 4 Cap 5 Valve Guide Oil Seal 6 Valve Stem Oil Seal 7 Damper 8 Outer Spring Index 90 816462 2 695 ENGINES 3A 21 Dipstick Specifications Oil Pan All Engines 9 UNIT OF MEASUREMENT H In mm a 1 2 7 25 7 16 646 a 181 CID 3 0L Engines 1 piece oil pan gasket 26 7 8 682 Removal das 3 4 1 Disconnect battery ADD AY NOTE Removal of engine from boat may be re quired 72887 2 Drain crankcase oll 41092 1 3 Remove starter motor MCM 4 Remove oil pan screws oil pan and gasket s Installation 1 Clean sealing surfaces of engine block and oil pan 2 Apply a small amount of Quicksilver RTV Sealer to joints of rear seal retainer and joints of front cover IMPORTANT Quicksilver RTV Sealer sets up in about 15 minutes Be sure to complete assembly promptly 3 Install oil pan gasket in position as shown Index N 3A 22 ENGINES 90 816462 2 695 NOTE A one piece oil pan gasket may be reused if it is still pliable and is not cracked torn or otherwise damaged 4 Install oil pan Starting from the center and work ing outward in each direction tighten 1 4 20 threaded fasteners to 80 l
52. s with care and do not attempt to force them through cylinder until cylin der is honed to correct size as this type piston can be distorted by careless handling 5 Thoroughly clean cylinder bores with hot water and detergent Scrub well with a stiff bristle brush and rinse thoroughly with hot water It is extremely essential that a good cleaning operation be per formed If any abrasive material remains in cylin der bores it will rapidly wear new rings and cylin der bores in addition to bearings lubricated by the contaminated oil Swab bores several times with light engine oil on a clean cloth then wipe with a clean dry cloth Cylinder should not be cleaned with kerosene or gasoline Clean remainder of cylinder block to remove excess material spread during honing operation PISTON SELECTION 1 Check used piston to cylinder bore clearance as follows a Measure cylinder bore diameter with a tele scope gauge 2 1 2 in 64 mm from top of cyl inder bore as follows Index 3A 46 ENGINES b Measure piston diameter at skirt across cen ter line of piston pin as shown 72911 c Subtract piston diameter from cylinder bore diameter to determine piston to bore clear ance d Determine if piston to bore clearance is in ac ceptable range shown in Specifications 2 If used piston is not satisfactory determine if a new piston can be selected to fit cylinder bore within acceptable range 3 If cylinder bor
53. size required 5 If within specifications measure new or used bearing clearances with Plastigage or equivalent IMPORTANT If bearing is fitted to out of round crankpin br sure to fit maximum diameter of crankpin If bearing is fitted to minimum diameter and crankpin is out of round 001 0 025mm in terference between bearing and crankpin will re sult in rapid bearing failure a Place a piece of guaging plastic the full width of crankpin parallel to crankshaft b Install bearing connecting rod and cap Index 90 816462 2 695 c Placea piece of gauging plastic the length of the bearing parallel to the crankshaft on the crankpin or bearing surface as shown Posi tion the gauging plastic in the middle of the bearing shell Bearings are eccentric and false readings could occur if placed else where B jia f A 72361 a Gauging Plastic d Install the bearing in the connecting rod and cap e Install the bearing cap and evenly torque nuts to 45 lb ft 61 N m IMPORTANT Do not turn the crankshaft with the gauging plastic installed f Remove the bearing cap and using the scale on the gauging plastic envelope measure the gauging plastic width at the widest point as shown d Ul hv i l im lu C oOo E n I HU N nnn sn 12342234 D L533 i ML 7 2 3 6 2 ENGINES 3A 31 6 If the clearance exceeds specifications select a
54. st be done slowly to allow lifter to adjust itself thus preventing possibility of the valve head con tacting the top of piston which may result in in ternal damage and or bent push rods 90 816462 2 695 Repeat Steps 2 3 4 to adjust other valves Install valve covers torque screws to 40 lb in 4 5 N m 7 Adjust carburetor idle mixture and idle speed Check for leaks Hydraulic Valve Lifters Hydraulic valve lifters require little attention Lifters are extremely simple in design Normally readjust ments are not necessary and servicing requires only that care and cleanliness be exercised in the handling of parts Locating Noisy Lifters Locate a noisy valve lifter by using a piece of garden hose approximately 4 ft 1 2 m in length Place one end of hose near end of each intake and exhaust valve with other end of hose to the ear In this man ner sound is localized making it easy to determine which lifter is at fault Another method is to place a finger on face of valve spring retainer If lifter is not functioning properly a distinct shock will be felt when valve returns to its seat General types of valve lifter noise are as follows 1 Hard rapping noise usually caused by plunger becoming tight in bore of lifter body so that return spring cannot push plunger back up to working position Probable causes are a Excessive varnish or carbon deposit causing abnormal stickiness b Galling or picku
55. tension 72308 a Valve Spring Tester J 8056 b Torque Wrench ENGINES 3A 19 Valve Seats Valve seat reconditioning is very important since seating of valves must be perfect for engine to deliver maximum power and performance Another important factor is valve head cooling Good contact between each valve and its seat in head is im portant to ensure that heat in valve head will be prop erly dispersed Several different types of equipment are available for reseating valve seats Equipment manufacturer s recommendations should be followed carefully to at tain proper results Regardless of type of equipment however it is es sential that valve guide bores be free from carbon or dirt to achieve proper centering of pilot in valve guide ensuring concentricity sf NA N A S TI N a eR 12338 a Check Valve Seat Concentricity Valves that are pitted must be refaced to the proper angle Valve stems which show excessive wear or valves that are warped excessively must be re placed When a valve head which is warped exces sively is refaced a knife edge will be ground on part or all of the valve head due to the amount of metal that must be removed to completely reface Knife edges lead to breakage burning or pre ignition due to heat localizing on this knife edge If the edge of the valve head is less than 1 82 in 0 8 mm after grind ing replace the valve Index 3A 20 ENGINES oeveral
56. tions a E E 3 Torque rocker arm nuts to 20 Ib ft 27 N m No d Push Rod valve adjustment is required Valve lash is auto e Rocker Arm Stud matically set when rocker arm nuts are torqued to specification Removal 4 Adjust carburetor idle speed and mixture NOTE When servicing only one cylinder s rocker arms bring that cylinder s piston up to TDC before re moving rocker arms When servicing all rocker arms bring No 1 piston up to TDC before removing rocker arms 1 Remove rocker arm covers as outlined 2 Remove rocker arm assemblies and push rods Index 90 816462 2 695 ENGINES 3A 11 Valve Adjustment Engine Not Running With valve cover removed adjust valves when lifter is on low part of camshaft lobe as follows 1 Crank engine with starter or turn over in normal direction of rotation until mark on torsional damp er lines up with center O mark on timing tab and engine is in No 1 firing position This may be de termined by placing fingers on No 1 valve as mark If valves move as mark comes up to timing tab engine is in No 4 firing position and should be turned over one more time to reach No 1 posi tion Na No 1 Cylinder Exhaust and Intake No 2 Cylinder Intake No 3 Cylinder Exhaust No 4 Cylinder Intake 50770 2 With engine in No 1 firing position as determined above the following valves may be adjusted 3 Back out adjusting nut until lash is felt at push
57. ts to 35 Ib ft 48 N m If reusing screws use Loctite 8831 6 Install flywheel housing and related parts Torque bolts to 30 Ib ft 41 N m 7 Install flywheel housing cover Torque bolts to 80 lb in 9 N m 8 Refer to SECTION 2 Removal and Installation and install engine ENGINES 3A 27 Rear Main Oil Seal The rear crankshaft oil seal can be replaced without removing the oil pan or rear main bearing cap from engine Removal Remove seal by using a screwdriver to pry it out of re tainer as shown O O O O a 0 72355 a Rear Seal b Seal Retainer C Slots Three Cleaning and Inspection Clean crankshaft seal running surface and seal re tainer IMPORTANT Correct rotation oil seal must be used to prevent oil leak Index 3A 28 ENGINES Installation 1 Apply Quicksilver Perfect Seal to seal retainer mating surface Apply grease to seal lips 2 Install seal using rear main seal installer 72356 a Rear Main Seal Installer J 26817 A Cleaning and Inspection 1 Clean gasket material from mating surfaces 2 Inspect oil seal retainer for cracks or scored sur face 3 Inspect oil seal for worn dry or torn rubber Re place if necessary refer to Rear Main Oil Seal as outlined 4 Inspect alignment pin for damage replace if nec essary Installation 1 Coat seal lips with clean motor oil 2 Install gasket and oil seal retainer with rear main seal
58. with loose fit in cylinder heads should be replaced with new oversize studs Studs may be installed after reaming holes as follows 1 Drain water from cylinder block 2 Remove old stud by placing Tool J 5802 01 over stud installing nut and flat washer and removing stud by turning nut a Tool J 5802 01 3 Ream hole for oversize stud with Tool J 5715 for 003 in oversize or Tool J 6036 for 013 in over Size 74289 a Reamer Tool J 5715 IMPORTANT Do not attempt to install an oversize stud without reaming stud hole 4 Coat press fit area of stud with Perfect Seal Install new stud using Tool J 6880 as a guide Gauge should bottom on head Index 90 816462 2 695 Valve Guide Bore Repair IMPORTANT Be sure to measure valve stem di ameter of both the intake and exhaust valve as valve stem diameter may or may not be the same for both valves If 015 in oversize valve stems are required ream valve guide bores for oversize valves as follows 1 Measure valve stem diameter of old valve being replaced and select proper size valve guide reamer from chart below 2 Ream valve guide bores as shown 72886 3 Remove the sharp corner created by reamer at top of valve guide Valve Springs Checking Tension Using valve spring tester as shown check valve spring tension with dampers removed Refer to Specifications IMPORTANT Springs should be replaced if not within 10 Ibs 44 N of specified
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