13
8. TROUBLE SHOOTING
ENGINE TROUBLE SHOOTING
SYMPTOM
POSSIBLE CAUSE
SOLUTION
Difficult to start, "fuel is
available,but no
SPARK at spark plug".
Spark plug bridging?
Check gap, insulation or replace spark plug.
Carbon deposit on spark plug?
Clean or replace spark plug.
Short circuit due to deficient spark plug
insulation?
Check spark plug insulation, replace if worn.
Improper spark plug gap?
Set to proper gap.
Difficult to start, "fuel is
available,and SPARK
is present at spark
plug.
ON/OFF switch is shorted?
Check switch wiring, replace switch.
Ignition coil defective?
Replace ignition coil.
Improper spark gap, points dirty?
Set correct spark gap and clean points.
Condenser insulation worn or short
circuiting?
Replace condenser.
Spark plug wire broken or short
circuiting?
Replace defective spark plug wiring
Difficult to start, "fuel is
available,spark is
present and
compression is normal"
Wrong fuel type?
Flush fuel system, and replace with correct
type of fuel.
Water or dust in fuel system?
Flush fuel system.
Air cleaner dirty?
Clean or replace air cleaner.
Difficult to start, "fuel is
available,spark is
present and
compression is low.
Suction/exhaust valve stuck or
protruded?
Re-seat valves.
Piston ring and/or cylinder worn?
Replace piston rings and or piston.
Cylinder head and/or spark plug not
tightened properly?
Torque cylinder head bolts and spark plug.
Head gasket and/or spark plug gasket
damaged?
Replace head and spark plug gaskets.
No fuel present at
carburetor.
Fuel not available in fuel tank?
Fill with correct type of fuel.
Fuel cock does not open properly?
Apply lubricant to loosen fuel cock level,
replace if necessary.
Fuel filter clogged?
Replace fuel filter.
Fuel tank cap breather hole clogged?
Clean or replace fuel tank cap.
Air in fuel line?
Bleed fuel line.
"Weak in power"
compression is proper
and does not misfire.
Air cleaner not clean?
Clean or replace air cleaner.
Improper level in carburetor?
Check float adjustment, re-build carburetor.
Defective Spark plug?
Clean or replace spark plug
"Weak in power"
compression is proper
but misfires
Water in fuel system?
Flush fuel system, and replace with correct
type of fuel.
Dirty spark plug?
Clean or replace spark plug.
Ignition coil defective?
Replace ignition coil.
Engine overheats.
Spark plug heat value improper?
Replace with correct type of spark plug.
Correct type of fuel?
Replace with correct type of fuel.
Cooling fins dirty?
Clean cooling fins.
Rotational speed
fluctuates.
Governor adjusted correctly?
Adjust governor.
Governor spring defective?
Replace governor spring.
Fuel flow restricted?
Check entire fuel system for leaks or clogs.
Recoil starter
malfunction.
Recoil mechanism clogged with dust and
dirt?
Clean recoil assembly with soap and water.
Spiral spring loose?
Replace spiral spring.
SYMPTOM
POSSIBLE CAUSES
SOLUTION
Travel speed too low,
and vibration is weak.
Engine speed too low?
Set engine speed to correct RPM.
Clutch slips?
Check or replace clutch.
V-belt slips?
Adjust or replace V-belt.
Excessive oil in vibration?
Drain excess oil and fill to proper level.
Malfunction in vibrator housing?
Check eccentric, gears and counter weights.
Bearing Failure?
Replace Bearing
Insufficient engine output?
Check engine, compression etc.
