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