Troubleshooting Tips And Pointers
Contents
1. Troubleshooting Tips And Pointers Here are some tips on finding and rectifying those troublesome niggles that everyone has either had or experiences Further help tips or pointers which aren t listed below would be greatly received Symptoms Possible cause Resolution Fuel Shortage Check there is fuel in the tank Blockage in carb jet or fuel line Check fuel is flowing from the tank to the carb remove pipe is necessary or use tickler No fuel in carb Check float is not stuck or jet blocked Carb flooded Wet spark plug insulator is obvious sign Kick over the engine with the throttle wide open and the fuel off to clear excess fuel Remove spark plug clean and dry in the Engine Fails to sunshine or warm place Start Spark failure Remove spark plug from cylinder head lodge on metal fins and kick over engine If you do not get a spark change the plug If still no spark check Points and condenser you should get a spark across the points as you open them with a screwdriver blade If not check battery and wires Change coil Fouled or Wiskered plug Clean or replace plug Two strokes suffer from wiskering where a deposit bridges the plug gap a remedy is a cooler plug or larger gap No electrical power Battery may be dead on battery ignition models is evident by no lights or horn Check the fuse if fitted Charge battery if dead Check clean and tighten battery terminals Bump start is possible on some models Disconnect battery ea2. rth lead and reconnect When started Slipped ignition timing If there is a spark check that it comes just Before top dead centre Check timing marks if present Engine runs Stale fuel Drain the fuel from the tank and refill with new poorly after period fuel of storage Gum deposits in carb Clean carb with suitable aerosol carb cleanser or metholated spirits Possible cause Symptoms Medium speed Mixture too rich Resolution Drain the fuel from the tank and refill with new misfire Magneto fault Check magneto for fault and repair Coil fault Weak mixture Engine overheating Replace coil Raise needle position increase main jet or adjust as per manufacturer instruction Ignition timing out Retime ignition to manufacturers settings Spark plug wrong grade Breaker points dirty or out of adjustment Replace with manufacturers recommended grade or equivalent Clean and adjust points HT pickup and slip ring dirty mag ignition Remove pickup wire wipe clean wipe collector ring while rotating engine Magneto or ignition coil fault Engine hard to start idles poorly or runs erratically Remove spark plug and check spark will jump gap 1 8 for magneto and 1 4 for coil when engine is turned over Check again when everything is warmed up to determine whether there is any deterioration Condenser fault Usually indicated by rapid pitting of the contact breaker points and
3. steady intense blue spark across the contacts whereas a small white spark is normal Ignition coil or condenser terminals loose Check and tighten Water in carb Drain carb bowl blow out jets and passage ways Carb out of adjustment or requires cleaning Adjust mixture and clean carb with suitable aerosol cleanser Fuel flow restricted Dirty plugs Check vent hole in filler cap is not blocked Clean plugs or replace Engine misfires when Weak spark Check ignition system accelerating Magneto pick up brush missing Replace Dirty pick up or collector ring Clean Plug cap or HT cable faulty Air leakage at carb flange Poor idle Replace Tighten do not over tighten as you will distort flange Replace gasket or rubber seal Air leakage in manifold balance pipe Worn carb slide and body Engine cuts out and Dirty spark plug Seal joint or replace pipe Replace carb Clean or replace spark plug misfires on load Plug gap to large Adjust to correct size Pronounced when climbing hils Weak spark or ignition trouble Blocked carb main jet Engine hesitates or dies Battery ignition check coil and set points Magneto ignition clean and set points check armature and condenser Remove main jet and blow through Avoid using a pin to clear when full throttle is applied Water in carb Drain and clean carb bowl jets and passages Mixture too weak Blue smoke from exha
4. ust when engine is warmed up Worn bore or piston rings Raise needle position increase main jet or adjust as per manufacturer instruction Replace piston rings Re bore fit new piston and rings Blue smoke from exhaust when changing gear Worn valve guides or valve stems Replace valves if the stem is worn or replace both guide and valve if excessive play in the guide Misfire in wet weather Short circuit of HT system Retarded ignition Poor top speed Faulty ignition auto advance performance Check plug cap coil and cable Use duck oil water repellant Check and set correctly Oil advance spindle check advance springs and establish functionality Dirty or blocked air filter Clean filter or replace cartridge Symptoms Blue smoke from exhaust when cold starting and when gear changing Contact breaker points burning Engine revs up but speed does not increase or kick start slips fails to turn engine over Possible cause Worn valve stems Resolution Replace valve and re cut seat Worn valve guides Replace valve and re cut seat Faulty condenser Replace condenser Loose condenser terminal Tighten terminal screw Dirty battery terminals Clutch slipping Clean and tighten terminals Adjust clutch pressure plate springs Replace clutch driving plates if friction material worn Add extra driven plate to increase pressure Blue smoke from exhaust
5. when cold starting Loss of performance due to poor compression Engine seizes or becomes tight after prolonged high speed Engine knocking when accelerating from low revs pinking Excessive vibration firing and kicking back Loose or worn engine mountings Tighten bolts or bush mounting holes to remove play Loose head stabiliser Tighten bolts Worn piston and crankshaft bearings Engine overhaul Worn gearbox main shaft bearings Gearbox overhaul Crankshaft unbalanced Wet sumping caused by leaking oil pump valves Oil settles in the sump pushes past the piston into the cylinder and burns off as blue smoke No valve clearance Balance crankshaft After standing a few days check the oil level before you start up the engine if it has dropped or low Recheck after running for a couple of minutes and it should have risen back to normal Not a major problem after periods of standing turn the engine carefully over on the kickstart about ten times before you switch on the fuel and ignition This will allow the oil pump to return some of the oil out of the sump before starting Alternative fix or replace oil pump non return valves Adjust tappets correctly Burnt valve seats Replace valve and recut seat Sticking valve Clean valve stems and remove gum Worn piston rings or bore Replace rings re bore if bore is badly worn Piston failure Plug pre ignition Usuall
6. y a holed piston accompanied by large amount of smoke from the exhaust caused by weak mixture Fit a cooler plug Piston seizure caused by incorrect piston clearance weak mixture or incorrect timing Resolve problem may require new piston or careful smoothing of surfaces Mixture weak Raise needle position increase main jet or adjust as per manufacturer instruction Oil pressure failure caused by lack of oil oil pump failure Ignition too advanced Automatic advance retard mechanism springs too weak Resolve problem may require new piston bore And cams or careful smoothing of surfaces Retard ignition by a degree or two Replace springs Engine needs de coke Ignition too advanced Auto advance unit stuck or broken spring Strip top end down and remove carbon from cylinder head and piston Retard ignition by a degree or two Strip unit and replace any broken parts
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