Gathering of the Green 2008 Winter Convention
Contents
1. May be stuck so tap to see if loosens on shaft Often worn also increases running timing If magneto shaft worn replace shaft expensive If driven flange worn replace Replace parts in order keep last spacer 85 Replace Impulse Spring in Wico C X Units 86 Replace spring in impulse cup Picture shows procedure Using pliers to wind can damage spring Replace spacer on shaft place cup over Shaft line up inner spring loop in both Spacer holes Carefully lift cup rotate CCW 1 full turn Replace nut and tighten smaller soacer washers available allows additional windup for hotter starting spark Wico C Service Information Install cover condenser points If new check carefully where the point spring attaches to the condenser bracket Common for edge of spring bracket to touch condenser bracket grounds out points e Problem worse with aftermarket kits Set points via edge gap distance Install rotor button and cap 89 Check point opening should be 0 015 If close leave as is as points set for max spark If not something else wrong have checked Install condenser and coil wires under point Spring screw Install rotor distributor cap Check for spark Do final timing when on tractor Service information for C X in SM 2029 FSB 127 C FSB 159 X Wico X Magneto 91 Replacement for Wico C and E S CD Better magneto AINiCo2. 6 screws holding front plate remove plate Leave 2 dowel pins which locate plate e Remove primary lead wire e Can now check coil points condenser 69 Coil Primary 0 5 ohms secondary 6000 ohms New coils are available Condenser Capacity 0 132 0 168 mfd Tecumseh 30548 B 0 172 mfd physically fits e Points Rework existing points Set opening to 0 015 e Additional work requires magnet charger Remove rotor clean amp repack bearings etc Typical problems Coil insulation drips into rotor causing it to stick Thumb nuts holding spark plug wires missing 70 e Reassemble magneto Reconnect primary wire Install new gasket line up dowel pins install cover e Mate L on distributor gear with pinion gear mark CD Service Information available includes Edison Splitdorf CD Service Manual JD Field Service Bulletin 125 JD Electrical Systems SM 2029 71 Edison Splitdort RM Magneto pere i 72 Rotating magnet design AINiCo magnet Model AA impulse unit different from CD Types used Spec 03509 e L621000 L622580 62 and unstyled L 10 6702 drive cup and 62953 gear Spec 03757 L625000 5 39 2 42 styled L 20 6734 drive cup and 62953 gear Used short magnetic rotor shaft Spec 03761 e L L639999 styled L e LA1000 LA4532 20 6733 drive cup and 62961 gear Used long magnetic rotor sha
3. March 1942 C furnished as AP replacement Points condenser coil most parts available e Model C issues Early versions had Zimac castings Stalk holding magnetic rotor came loose Damaged rotor and pole faces point opening varies Wico improved design noted by 3 cast in frame Always ensure magnetos have the 3 cast in Later versions had aluminum castings 82 e Remove distributor cap make sure rotor button is not loose on magnetic rotor shaft If loose replace it Try to wiggle end of rotor shaft Problems if it moves Loose stalk replace case Worn bushings replace Allows timing to vary as point opening varies in time Rotate shaft to open close points Check if movable point loose on pivot pin e Remove points and condenser Be careful to note locations of point spacers 83 Check condenser 0 16 0 20 mfd no leakage Replace if bad Check points clean and hone smooth Check rubbing block if worn replace Check coll Primary 0 42 ohms secondary 5000 ohms If secondary open replace Inspect impulse end for wear Check where drive cup edge meets driven flange if worn increases running timing e Remove drive cup nut and drive cup Pry out impulse spring clean re grease e Remove spacers washers spring retainer Inspect where driven flange rotor shaft meet Should not be able to rotate flange on shaft
4. Shuttle wound armature R2 use began on the C at 200111 Used on all GP series tractors until GPWT 405109 RV series introduced July 1933 First rotating magnet design Chrome steel magnets Furnished to Deere have D prefix Base mount DRV2 used on GPWT 405110 end Flange mount DRV2A used on A series Flange mount DRV2B used on A and B series Spark at uneven intervals 180 540 Click spark click spark click no spark click no spark Fairbanks Morse R2 John Deere Magneto 58 Deere unhappy with FM service documented Letter to FM Dec 20 1934 lists complaints FM needs to provide same high level of service obtained from other manufacturers Magnetos not efficiently serviced Require re servicing too quickly Service costs too much FM letter Jan 15 1935 to their Service Stations Read enclosed JD letter Get supply of parts Need to render real service e Deere starts experimenting with Wico June 17 1936 first use of AP477 on B Last use of FM magneto by Deere Oct 1937 59 Impulse units on DRV2A DRV2B Lag angle determined by key position in drive member not drive cup Drive cups same drive members labeled Wico drive member fixed to rotor shaft lag angle determined by drive cup Lag angle NOT adjustable as on Wico magnetos pawl stop is a fixed pin Running timing cannot be adju
5. is a critical position during rotation of the magnetic rotor Magnetic field collapsing and reversing in coil Maximum current is flowing in the primary and opening the points at that point in the rotation produces the best spark Critical rotor position is the distance between the edge of the magnet and the trailing pole face and is called the Edge Gap 0 095 wire gives correct Edge Gap 21 Edge gap distance Distance between magnet edge and trailing pole face Determined during magneto PH MT TT design ATRIA The cam which opens the P EDGE GAP i points is part of the magnetic rotor shaft set points to open when rotor position is at edge gap Ensures hottest spark possible Setting the point gap approximates the edge gap What does Setting the Points mean Rotate magnetic rotor and cam until point rubbing block is on highest part of cam Adjust stationary point to proper gap Rotate magnetic rotor back until points JUST Start to open The trailing edge of the rotor should be at the edge gap distance from the pole face So setting the points approximates setting the edge gap Not as accurate due to cam wear worn bushings or worn rubbing block 23 Splitdorf Dixie Aero 246C T Point gap 0 020 edge gap 0 020 Fairbanks Morse DRV2A B Point gap 0 012 edge gap 0 203 Edison Splitdorf CD Point gap 0 015 edge gap 0 0
6. lines of force flow out of left end N pole of magnet through coll back to right end S pole 2 ALLL LLL Less of rotor covered by core so magnetic field through coil also decreases Changing flux causes current to flow in coil primary points closed cas mar ar B IBA UA SA ge m rar I e Prior to points opening primary current in coil resists flux decrease e When points open effect is gone resulting in extremely rapid change in flux Here primary current has reached maximum value and points are opening edge gap Primary resistance increases from 0 5 ohms to infinite as points open Current drops to zero Voltage spikes Arc at points as they open e Condenser absorbs arc energy reduces arc iii Points open arc stops Flux reverse through coil complete Condenser discharges back into coil primary Aids flux reversal e Flux reversal induces high voltage in coll secondary Edge gap Points open Maximum HV Secondary voltage overcomes plug gap resistance get spark Current flow across plug gap resistance decreases secondary continues to discharge Flux change inhibited extends time of spark p 0 o O ce m o e Magnetic rotor has moved 180 flux reestablished in opposite direction Cycle repeats to produce two sparks per rotor revolution e There
7. the pawl and pushes it off the stop Energy stored in impulse spring is released the rotor snaps forward rapidly passes through the edge gap and stops against the drive cup e As the rotor passes the edge gap distance the points open and a Spark is produced at TDC Difference between running and impulse timing is the lag angle 34 e Achieves two goals Provides mechanism to delay spark Increases spark intensity for easier starting Operation Magnetic rotor shaft rotates slowly Pawl on driven flange rotates out catches stop Magnetic rotor stops Drive cup continues to rotate Winds up impulse spring about 70 As drive cup lugs approach horizontal edge of drive cup strikes pawl pushes it off stop 35 Impulse Unit Operation Pawl striking trip arm spring windup starting Impulse Unit Operation Drive cup pushing pawl off impulse stop 37 Operation cont d Energy stored in impulse spring is released Rotor snaps forward Rapidly passes through the edge gap stops against the drive cup As rotor passes the edge gap distance points open and spark is produced at TDC Rotor speed 800 rom Pawls drop out at 220 rom Difference between running and impulse timing is the lag angle 38 e Wico has an adjustable impulse stop Other brands used on Deere use fixed stops Accomodates Impulse timing changes when magneto is rotated to fine tune r
8. used until late 20 or 21 Replaced by AERO Used until end of production e CCW rotation base mount e 30400 35308 AD116R Aero 246C magneto with Sumter Model B impulse using a top switch to set trip Spec 136115 35309 81069 AD295R Aero 246C magneto with Splitdorf Model EM enclosed impulse unit with side switch for trip Spec 136116 e 81070 130699 AD597R Aero 246T magneto with EM impulse Spec 136540 246C had brass sides and cover 2461 had zinc alloy cast sides and cover 52 Splitdorf Aero 246C with B2 Impulse Unit 53 oplitdorf 246T Magneto with EM Impulse Unit A i is FR SSN a SS P i I a gt bad i Li L u 5 a gt Splitdorf 246T with EM Impulse Unit 54 e Disassembly straightforward Remove covers impulse unit magnets Remove condenser coil Pot metal base and end plates Check for looseness of rotor and bearings Bearing cups become loose in end plates problem Check coll Primary 0 5 ohms secondary 7000 ohms Replacement coils available e Check condenser 0 09 0 11 mfd Often leaky use a modern replacement with a working voltage gt 500 volts 55 Be careful to line up timing dots on pinion and distributor gear Point setting 0 022 Make sure they fit together squarely Splitdorf service information IH Magneto Manual Magneto development started in 1921 R series introduced in 1924
9. 42 RM Point gap 0 015 edge gap lt 0 125 e Wico AP C X Point gap 0 015 edge gap 0 095 Basics Drive cup slot in end of governor shaft e Drives magneto e Rotates in same direction and rate as flywheel Horizontal when piston at TDC 1937 SAE Standard Magneto impulse spark occurs LH Impulse flywheel mark e Lines up with mark at 3 00 on transmission housing One piston is at TDC 30 below transmission mark piston 30 BTDC Flywheel side plug fires 180 later pulley side 25 e First discuss running timing Example John Deere A Wico C or X magneto Choose 30 BTDC for spark to occur Magneto produces spark when magnetic rotor is at Edge Gap distance Fixes position of magnetic rotor Key element is the magneto drive cup Connects the magnetic rotor to drive slot 26 Driven Flange Group Fixed to rotor by mated flat on shaft Drive cup Edge held against driven flange by impulse spring inside cup Drive cup free to turn on rotor shaft Running timing is determined by drive cup Cup shown is 25 drive cup Blue edge is for 30 orange for 35 Wear points Driven flange on rotor shaft Drive cup on driven flange e Back to example want spark with pistons at 30 BTDC Flywheel is 30 BTDC Drive slot at 30 BTDC Magneto has 30 drive cup When rotor at edge gap distance magneto drive cup f
10. 477B only from B49200 89999 Used on A from 478500 488000 76 Wico introduced model C January 1939 Used immediately on Deere H Jan 1939 e Nebraska test on H1000 Oct 38 used E S RM Then exclusively on the e Bat 90000 Feb 1940 A at 488000 July 1940 L at 640000 7 17 41 LA at 4533 July 1941 e Gat 11981 10 1 41 Tried on D at 152708 1942 But the D continued mostly with the E S CD 0010 The C was used until introduction of the X 77 Wico introduced the model X Aug 1946 Available as X H orizontal and X V ertical Featured better magnetic rotor design AINiCo replaced the Nipermag rotor Improved bearing design Replaced the model C on the A at 598519 Dec 1947 to 659289 XB B at 217799 Dec 1947 to 268819 XB G at 29248 Jan 1948 to 46500 D R And the E S CD spec 0010 on the D at 187103 Oct 1949 to end Well built magneto rotor spins on needle bearings available Coils available not points and condensers NOS points around rebuild condenser Condenser value 0 16 0 20 mfd Impulse drive cup spring not available 5 16 wide C amp X springs 1 wide Overhaul instructions in SM 2029 FSB 126 Wico C Magneto nea TE EP ii LL MIE 81 e Replacement for AP series Needle bearings to bushings Cheaper AP Aug 1939 list price 37 20 e C March 1941 list price 24 50 FSB 131
11. D 25 66 x 25 360 4 583 4 19 32 D 30 66 x 30 360 5 500 5 1 2 D 35 66 x 35 360 6 417 6 13 32 D 40 66 x 40 360 7 333 7 11 32 Measure off and chalk these distances CCW starting at the LH Impulse mark 42 Locate a timing light and battery to run it Hook spark sensor to 1 plug wire Start tractor being careful to leave marks With the timing light in the plane of the flywheel center and mark on transmission case see which mark lines up with case RPM does not matter Get about 10 change by rotating magneto If the 35 mark lines up and you want 30 timing rotate magneto forward Forward retards spark back advances spark After running time is correct set start timing Stop engine remove timing light mark position of magneto so it can be replaced accurately Rotate flywheel note where impulse occurs relative to LH Impulse mark Adjust Impulse Stop Ring for spark at TDC or 1 3 ATDC If magneto impulses after LH Impulse has passed mark impulse stop ring will be rotated CW Remove magneto loosen four screws holding impulse stop ring rotate stop ring tighten screws Each cast in mark in case near top of stop ring is 5 Replace magneto lining up with mark check impulse time if not correct redo last steps 4 e Now both running and starting timing are set to proper values If rotation of magneto does not provide desir
12. Gathering of the Green 2008 Winter Convention March 12 15 Moline IL Magnetos History Application and Servicing Splitdorf Fairbanks Morse Wico Edison Splitdorf Duane Larson Knoxville TN e Magnetos require periodic servicing and repair to properly perform their function Provide an adequate spark at the proper time to the spark plug Several knowledgeable people have led this workshop in the past Covered mainly Wico C and X series have researched and rebuilt magnetos for over 25 years Expand workshop to cover magnetos which came on Deere tractors from the factory Several folks have provided me information Mark Maikshilo Mark s Magneto Service Steve Ridenour and Jack Kreeger Y and 62 John Nikodym early D magnetos e References Magneto manuals Deere parts books and SM 2029 Electrical Manual Field Service Bulletins Public libraries Flint MI and Indianapolis IN le ente Application Chart plus other Handouts from the Gathering of the Green workshops are among the information included on the CD available through this web site e Magneto talk was long several slides not used for time consideration Noted by EXTRA in Title box at top of slide Included here because often contain useful information However in the presentation summary slides were sometimes used May affect flow of information if confusing just skip slides with EX
13. TRA in title Magneto theory and operation Edge gap and point setting Engine and magneto timing Impulse and running Specific magnetos used by Deere Splitdorf Fairbanks Morse Edison Splitdorf Wico Repair suggestions included for each magneto e Magneto theory How a Spark is produced Magneto operation and timing Getting a spark at the correct time Impulse and running e Apply these principles to magnetos found on Deere tractors from the factory Splitdorf Dixie Aero 246C 246T Waterloo Boy D Fairbanks Morse DRV2A B A B Edison Splitdorf CD RM A D G L LA Wico AP C X A B D G H L LA History and Servicing information e Magneto converts mechanical energy into electrical energy Magnetos DO NOT use batteries Wico XB distributor looks like a magneto Faraday s Law any relative motion between magnet and wire induces current flow In wire Magneto Classification Low tension provide spark for ignitors High tension provide spark for spark plugs High Tension magneto classification Shuttle wound stationary magnet rotating coil Fairbanks Morse R2 on GP series Rotating inductor stationary magnet and coil rotating flux reverser armature Splitdorf Dixie Aero Rotating magnet stationary coil Fairbanks Morse DRV2A B all Edison Splitdorf Wico Common after AINiCo magnet became avail
14. able e Base or Flange mount All Deere tractors use flange mount except Waterloo Boy D 30401 130700 All GP series including C e Magnets Prior to 1917 magnet steels were used most commonly alloyed with tungsten or chromium Cobalt steel was introduced in 1917 with improved retentivity Cobalt chromium steel came in 1921 Typical horseshoe magnet on magnetos In 1935 aluminum nickel cobalt AINiCo steel was introduced Huge improvement in magnetic retentivity Allowed practical use of rotating magnet magneto Still used today PRIMARY WINDING SECONDARY WINDING C IR PUT CRA AAPA AAA AASV O LAMINATED IRON P COIL CORE COMMON GROUND LAMINATED ROTOR IRON CORE POLES MAGNETIC ROTOR Purpose is twofold Reduce sparking at points e As points open condenser absorbs energy from collapsing magnetic field lessens sparking Increase rate of collapse of magnetic field As condenser discharges back through coil primary it increases high voltage available from coil secondary e Choice of condenser Based on choice of coil and cam properties during magneto design Coil cam and condenser choices are a significant engineering design issue AT AU S Al att HET HHL i ALII PTT LETHE rf OTIR Ti VALLE Magnetic
15. ce information available Handouts from the Gathering of the Green workshops are among the information included on the CD available through this web site 97
16. ctor Remove spark plugs Rotate flywheel until 1 on compression stroke Not every magneto impulse generates spark Click Spark click spark click no click no RH bottom terminal provides 1 spark then LH top Lay plug on magneto connect to RH terminal Turn impulse with wrench observing sparks When plug fires stop turning mate horizontal magneto drive cup to horizontal slot on governor Attach magneto RH bottom plug wire to 1 LH top wire to 2 Time magneto with timing light 66 History Edison company wanted to make radios No licenses being sold bought Splitdorf for license Formed Edison Splitdorf subsidiary of Edison Co October 1932 Made spark plugs and magnetos Edison Splitdorf Model CD announced Jan 36 First use by Deere on Model D November 1936 Followed by use on Model G in May 1937 Model A in Fall 1937 Edison Splitdorf Model RM announced Feb 37 First magneto with AINiCo magnetic rotor First use on Model 62 March July 1937 67 Edison Splitdorf CD Magneto B fs 68 Rotary Inductor design Stationary coil and magnet Rotate legs of magnetic circuit to reverse field in coil Carry over from AERO design Model AA impulse unit Check to hear feel impulse clunk e Disassembly remove Distributor block rotor safety gap Rotor pin offset so goes on only one way
17. ed run timing Change drive cup Lift governor box rotate governor drive gear 1 tooth Backward spark occurs 12 15 later most common Forward spark occurs earlier If timing light shows spark jumping in time Loose distributor rotor Worn bushings Loose point pivot pin 45 Up to now information has been general applying mostly to all magnetos Look at specifics of magnetos Splitdorf Dixie Aero 246C 246T Waterloo Boy D Fairbanks Morse DRV2A B A B Fairbanks Morse R2 used on GP series Cork Groth seminar Edison Splitdorf CD RM A D G L LA Wico AP C X A B D G H L LA History Application and Servicing information 46 NEVER charge magnets with the impulse unit on Impulse dogs get magnetized slow to drop out Always remove magneto for governor work Disconnect coil and condenser before testing Always use a flange gasket Ensure ventilation holes open in caps If impulse unit doesnt snap broken spring Really messes up timing tractor runs poorly Changing point gap changes timing 2 points of resistance when turning drive cup Get a parts book which shows exploded view of magneto n a for Splitdorf magnetos 47 Splitdorf Company began in 1858 Spark plugs by 1903 Magnetos by 1908 shuttle wound Sumter Magneto Co Sumter SC Charles Mason patented new type magneto Based on Mason Principle
18. ft 13 e Remove the distributor cap and rotor Clean rotor disk with eraser e Remove points and condenser for inspection and servicing Neither are readily available no longer made Condenser has value 0 19 mfd Point spring attaches to condenser can Modify condenser for diesel pony motor Too much capacitance 0 33 mfd e Remove coll cover to check coll Primary 0 4 ohms secondary 5000 ohms New coils are available May have to remove coil to clean up tar from coil e Replace coil cover using new gasket e Check brushes in distributor cap Set points to 0 015 Time magneto to tractor Verify correct gear 10 thru unstyled L 20 rest Move timing hole cover on bell housing Turn motor until SPARK on flywheel in hole center Turn rotor CW until center of copper is next to grounding button then turn until points open Rotate magneto top to the right mesh magneto gear with driving gear Rotate magneto left to keep rotor from moving push in place adjust so points just opening fasten in place Started as Witherbee Igniter Company 1897 e Developed EK magneto 1919 22 Over 1 million sold for 1 cylinder farm engines 1920 changed name to Wico e Developed good rotating magnet designs Implemented in models A and AP June 17 1936 first use of Wico magneto by Deere AP477B on B 24050 Deere flip flopped between AP477 amp DRV2B Used AP
19. its into slot Sparks occur at 30 BTDC with tractor running How do we get the starting timing at TDC with 30 drive cup e Determine when engine requires spark Starting at Top Dead Center TDC Running choose 30 BTDC for our example Distillate burners 35 gasoline burners 25 e Determine when magneto produces spark Couple magneto to tractor to get spark at right time Accommodate both starting and running timing For example choose simple case John Deere A Wico C or X magneto Flywheel left 1 side spark plug fires first followed 180 later by pulley right 2 side spark plug Want starting spark on flywheel side at TDC Remove spark plugs put thumb over hole rotate flywheel slowly until air pushes on thumb compression stroke Continue to rotate until LH Impulse line on flywheel lines up with mark on transmission case Late A punch mark on flywheel hub lines with V on cover Confirm TDC Wire in spark plug hole Remove crankcase cover visual inspection When all is correct magneto drive flange will be horizontal S A E Standard adopted January 1937 revised 1941 30 Magneto Timing Wico C or X EXTRA Magneto produces spark when magnetic rotor is at edge gap distance Fixes position of magnetic rotor Driven Flange Group is positioned on rotor by machined flat on shaft Drive cup lip is held against driven flange by i
20. magnetic rotor hotter spark Bearing on outboard end of magnetic rotor No stalk to come loose e Common troubles Rotor button comes loose e Can replace just spring Coil clamps crack and break get into magnetic rotor Bearing goes bad rust dirt sticks 92 Remove cover check rotor button Remove condenser points Check condenser value depends on coil used X5700C stamped capacitance 0 30 0 34 mfd Or hot coil Taped coil 0 16 0 20 mid e Remove coil clamps check for cracking If cracked replace e Check coil resistance Primary 0 50 ohms secondary 7500 ohms 93 e Check ease of rotation If rotates freely except for two points of resistance per revolution bearing ok lf not must disassemble impulse unit completely replace bearing 6201 e Install points Set points via edge gap distance e Install rotor button cover 94 95 Check point opening should be 0 015 If close leave as is as points set for max spark If not something else wrong have checked Install rotor cover Check for spark Do final timing when on tractor Discussed OEM magnetos for all Deeres Seen improvements in magnetos How to time magneto to tractor Importance of correct drive cup Advantage of adjustable impulse on Wicos Highlights of service for magnetos Handouts contain application details Servi
21. mpulse spring inside cup Drive cup is free to turn on rotor shaft Running timing is determined by relative position of cup and flange Cup shown is for 25 drive cup Blue edge is for 30 orange for 35 e Running timing is determined by the choice of drive cup Only variable in the whole system 3744 35 deg long lug 4702 35 deg long lug Va lugs 3565 35 deg short lug 2061B 30 deg short lug e 7596 25 deg long lug hard to find e 6274 25 deg short lug 2040 20 deg short lug gear driven 32 e The governor drive cup slot and flywheel rotate in the same direction at same rate e When the flywheel and crank and pistons is 30 before TDC The magneto drive slot is 30 BTDC 8 00 2 00 position The 30 drive cup on the magneto is also in the 8 00 2 00 position when the rotor is at the edge gap distance A spark is produced and the engine fires at 30 BIDC But how do we get the starting timing to be at TDC with a 30 drive cup 33 Achieves two goals Provides mechanism to delay spark Increases spark intensity for easier starting Operation Magnetic rotor shaft rotates slowly during starting process Pawls on driven flange group rotate out catch stop When pawl strikes stop magnetic rotor stops but drive cup continues to rotate and winds up impulse spring about 70 When the drive cup lugs are nearing horizontal an edge of the drive cup strikes
22. rotary inductor design Revolutionary named magneto line DIXIE Splitdorf bought all patents manufacturing capabilities for 1 million in August 1915 Sumter Division in Chicago built DIXIE magnetos Mostly for 1 cylinder engines prior to Splitdorf purchase Splitdorf developed the Model 46 and 246 Neither Sumter or Splitdorf names appear Only DIXIE inside Splitdorf Trademark Splitdorf AERO announced between March and August 1920 Change to rotor pole faces cam and condenser provided all sparks with the same polarity All spark plugs want a negative center terminal Added suffix C to model Now 46C 246C Splitdorf Electrical Company and AERO replaced DIXIE on the brass cover DIXIE AERO doesn t exist Summary in J R Hobbs Unstyled Deere book KW Kingston Sevison Swiss and DIXIE on R Instruction Book price list No 3 for R Instruction Book price list No 5 dated 8 1 1917 CW rotation Model N Instruction Manual No 7 April 1 1920 DIXIE only used on N through end of production Models 46 246 listed e Same except for 4 46 or 2 246 terminal distributors Parts Catalog No 26 1926 Lists 46 246 46C 246C Assume went from 246 to 246C by late 20 or 21 50 Summary in J R Hobbs Unstyled Deere book KW Kingston Sevison Swiss and DIXIE on R Instruction Book price list No 5 8 1 1917 CW rotation DIXIE
23. sted separately from impulse timing as can be done on Wico 60 Fairbanks Morse DRV2A Magneto 61 e DRV2A A 410000 424024 AR AO 250000 251485 Two different impulse units used YB pressed steel drive cup welded lugs Replaced at magneto s n 136200 by XD machined drive cup UB3 modern replacement unit forged drive cup short lug drive cup used 62 Fairbanks Morse DRV2B Magneto 63 e DRV2B Model B has gas tank flange 12 closer to governor box not room for DRV2A Goal was to use same magneto on A and B rotated magneto body 90 leave flange same Provided adequate clearance for plug wires Problem with B flywheel casting used p n AB210R until B14038 after which AB706R was used on both A and B Interesting story here Long lug drive cup 35 lag angle YB and XD impulse units used as for DRV2A 64 e Deere provided a DRV2A B Service Manual Remove top cover New gaskets available Check coil correct replacements available Primary 0 5 ohms secondary 5000 ohms Remove end cap New gaskets not available To replace condenser must remove points and distributor assembly clean both Check condenser 0 19 0 21 mfd Unsolder can remove stuffing solder in modern capacitor e Remove impulse unit magnetic rotor bearings Reassemble set points 0 012 check gear timing 65 Time magneto to tra
24. unning timing Accumulated wear in magneto and gears that drive the magneto e Running timing determined by drive cup Impulse timing determined by position of impulse stop 39 Can use impulse stop to approximate running timing Assuming no wear in magneto or drive gears Set points at 0 015 approximates E gap Set impulse stop at degrees of running timing of drive cup Handouts from the Gathering of the Green workshops are Use marks cast in housing J among the information Details in 72 Mount magneto rotate backward until impulse trips lock down 40 Rotate flywheel so 1 piston is at TDC on compression stroke air rushes from plug hole Magneto drive slot horizontal Hold magneto in a vise in the same position as on tractor Connect plug wires from magneto to spark plugs ground spark plug case to vise Rotate drive cup with wrench until spark occurs at plugs Drive cup lugs will be horizontal Not all magnetos provide a spark every impulse Rotate enough times until you know which plug fires first followed by spark at second plug 1 2 turn later Rotate until spark occurs at first plug and stop Put magneto on tractor without rotating drive cup Install spark plugs and plug wires first to 1 second to 2 A e Measure circumference of flywheel About 66 for Model A Calculate distances for different timings Distance circumference x deg adv 360
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