Operations Manual

18
3.7.2 Engine Troubleshooting
SYMPTOM
POSSIBLE CAUSES SOLUTION
Diicult to start, fuel is
available, but no SPARK
at spark plug.
Spark plug bridging.
Carbon deposit on spark plug.
Check gap, insulation or replace
spark plug.
Clean or replace spark plug.
Short circuit due to deficiency.
Improper spark plug gap.
Check spark plug insulation, replace if
needed.
Set to proper gap.
Diicult to start, fuel is
available, SPARK is
present and compression
is normal.
Wrong fuel type.
Water or dust in fuel system?
Flush fuel system and replace with
correct type of fuel.
Flush fuel system.
Air cleaner dirty.
Clean or replace air cleaner.
Diicult to start, fuel is
available, and SPARK is
present at spark plug.
ON/OFF switch is shorted.
Ignition coil defective.
Check switch wiring, replace switch.
Replace ignition coil.
Improper spark gap, points dirty.
Condenser insulation worn or
short circuiting.
Set correct spark gap and clean points.
Replace condenser.
Spark plug wire broken or
short circuiting.
Replace defective spark plug wiring.
Diicult to start, fuel is
available, spark is
present and
compression is low.
Suction/exhaust valve stuck or
protruded?
Piston ring and/or cylinder worn. Replace piston rings and or piston.
Cylinder head and/or spark plug
not tighetened properly.
Head gasket and/or spark plug
gasket damaged.
Torque cylinder head bolts and spark
plug.
Replace head and spark plug gaskets.
“Weak in power”
compression is proper
but misfires.
Water in fuel system.
Dirty spark plug.
Clean or replace spark plug.
Flush fuel system and replace with
correct type of fuel.
Ignition coil defective.
Replace ignition coil.
No fuel present at
carburetor.
Fuel not available in fuel tank.
Fuel cock does not open properly.
Fill with correct type of fuel.
Apply lubricant to loosen fuel cock
level, replace if necessary.
Fuel filter clogged.
Fuel tank cap breather hole
clogged.
Replace fuel filter.
Clean or replace fuel tank cap.
Air in fuel line. Bleed fuel line.
Re-seat valves.