0-20
Troubleshooting
Engine doesn't start or is difficult to start
1 Starter motor does not rotate
1 Engine kill switch Off.
2 Fuse blown. Check fuse block (Chapter 8).
3 Battery voltage low. Check and recharge battery (Chapter 8).
4 Starter motor defective. Make sure the wiring to the starter is
secure. Test starter relay (Chapter 8). If the relay is good, then the fault
is in the wiring or motor.
5 Starter relay faulty. Check it according to the procedure in
Chapter 8.
6 Starter switch not contacting. The contacts could be wet,
corroded or dirty. Disassemble and clean the switch (Chapter 8).
7 Wiring open or shorted. Check all wiring connections and
harnesses to make sure that they are dry, tight and not corroded. Also
check for broken or frayed wires that can cause a short to ground (see
wiring diagram, Chapter 8).
8 Ignition switch defective. Check the switch according to the
procedure in Chapter 8. Replace the switch with a new one if it is
defective.
9 Engine kill switch defective. Check for wet, dirty or corroded
contacts. Clean or replace the switch as necessary (Chapter 8).
2 Starter motor rotates but engine does not turn over
1 Starter motor clutch defective. Inspect and repair or replace
(Chapter 8).
2 Damaged idler or starter gears. Inspect and replace the damaged
parts (Chapter 2).
3 Starter works but engine won't turn over (seized)
Seized engine caused by one or more internally damaged
components. Failure due to wear, abuse or lack of lubrication. Damage
can include seized valves, valve lifters, camshaft, pistons, crankshaft,
connecting rod bearings, or transmission gears or bearings. Refer to
Chapter 2 for engine disassembly.
4 No fuel flow
1 No fuel in tank.
2 Fuel tap vacuum hose (if equipped) broken or disconnected.
3 Tank cap air vent obstructed. Usually caused by dirt or water.
Remove it and clean the cap vent hole.
4 Inline fuel filter clogged. Replace the filter (Chapter 1).
5 Electric fuel pump not working (if equipped). Test it according to
the procedures in Chapter 8.
6 Fuel line clogged. Pull the fuel line loose and carefully blow
through it.
7 Inlet needle valve clogged. For both of the valves to be clogged,
either a very bad batch of fuel with an unusual additive has been used,
or some other foreign material has entered the tank. Many times after a
machine has been stored for many months without running, the fuel
turns to a varnish-like liquid and forms deposits on the inlet needle
valves and jets. The carburetors should be removed and overhauled if
draining the float chambers doesn't solve the problem.
5 Engine flooded
1 Fuel level too high. Check and adjust as described in Chapter 3.
2 Inlet needle valve worn or stuck open. A piece of dirt, rust or other
debris can cause the inlet needle to seat improperly, causing excess
fuel to be admitted to the float bowl. In this case, the float chamber
should be cleaned and the needle and seat inspected. If the needle
and seat are worn, then the leaking will persist and the parts should be
replaced with new ones (Chapter 3).
3 Starting technique incorrect. Under normal circumstances (i.e., if
all the carburetor functions are sound) the machine should start with
little or no throttle. When the engine is cold, the choke should be
operated and the engine started without opening the throttle. When the
engine is at operating temperature, only a very slight amount of throttle
should be necessary. If the engine is flooded, turn the fuel tap off and
hold the throttle open while cranking the engine. This will allow
additional air to reach the cylinders. Remember to turn the fuel tap
back on after the engine starts.
6 No spark or weak spark
1 Ignition switch Off.
2 Engine kill switch turned to the Off position.
3 Battery voltage low. Check and recharge battery as necessary
(Chapter 8).
4 Spark plug dirty, defective or worn out. Locate reason for fouled
plug(s) using spark plug condition chart and follow the plug
maintenance procedures in Chapter 1.
5 Spark plug cap or secondary (HT) wiring faulty. Check condition.
Replace either or both components if cracks or deterioration are
evident (Chapter 4).
6 Spark plug cap not making good contact. Make sure that the plug
cap fits snugly over the plug end.
7 Igniter defective. Check the unit, referring to Chapter 4 for details.
8 Pickup coil(s) defective. Check the unit(s), referring to Chapter 4
for details.
9 Ignition coil(s) defective. Check the coils, referring to Chapter 4.
10 Ignition or kill switch shorted. This is usually caused by water,
corrosion, damage or excessive wear. The switches can be
disassembled and cleaned with electrical contact cleaner. If cleaning
does not help, replace the switches (Chapter 8),
11 Wiring shorted or broken between:
a) Ignition switch and engine kill switch (or blown fuse)
b) Igniter and engine kill switch
c) Igniter and ignition coil
d) Ignition coil and plug
e) Igniter and pickup coil(s)
Make sure that all wiring connections are clean, dry and tight.
Look for chafed and broken wires (Chapters 4 and 8).
7 Compression low
1 Spark plug loose. Remove the plug and inspect the threads.
Reinstall and tighten to the specified torque (Chapter 1).
2 Cylinder head not sufficiently tightened down. If a cylinder head is
suspected of being loose, then there's a chance that the gasket or
head is damaged if the problem has persisted for any length of time.
The head nuts and bolts should be tightened to the proper torque in
the correct sequence (Chapter 2).
3 Improper valve clearance. This means that the valve is not closing
completely and compression pressure is leaking past the valve. Check
and adjust the valve clearances (Chapter 1).
4 Cylinder and/or piston worn. Excessive wear will cause
compression pressure to leak past the rings. This is usually
accompanied by worn rings as well. A top end overhaul is necessary
(Chapter 2).
5 Piston rings worn, weak, broken, or sticking. Broken or sticking
piston rings usually indicate a lubrication or carburetion problem that
causes excess carbon deposits or seizures to form on the pistons and
rings. Top end overhaul is necessary (Chapter 2).
6 Piston ring-to-groove clearance excessive. This is caused by
excessive wear of the piston ring lands. Piston replacement is
necessary (Chapter 2).
