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page 38 — MQS36H SeRIeS WaLK-BeHIND TROWeL • OpeRaTION aND paRTS MaNUaL — Rev. #0 (03/08/12)
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Troubleshooting (engine)
Symptom
possible problem
Solution
Diffi cult 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 defi cient spark plug
insulation?
Check spark plug insulation, replace if worn.
Improper spark plug gap?
Set to proper gap.
Fuel reaching carburetor?
Check fuel line.
Water in fuel tank?
Flush or replace fuel tank.
Fuel fi lter clogged?
Replace fuel fi lter.
Stuck carburetor?
Check fl oat mechanism.
Spark plug is red?
Check transistor ignition unit.
Spark plug is bluish white?
If insuffi cient compression, repair or replace
engine. If injected air leaking, correct leak. If
carburetor jets clogged, clean carburetor.
No spark present at tip of spark plug?
Check transistor ignition unit is broken, and
replace defective unit. Check if voltage cord
cracked or broken and replace. Check if
spark plug if fouled and replace.
No oil?
Add oil as required.
Oil pressure alarm lamp blinks upon starting?
(if applicable)
Check automatic shutdown circuit, "oil
sensor". (if applicable)
Diffi cult to start, fuel is available, and spark is
present at the 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.
Diffi cult 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.
Choke open?
Close choke.
Diffi cult to start, fuel is available, spark is
present and compression is low.
Suction/exhaust valve stuck or protruded?
Reseat 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.
No fuel in fuel tank?
Fill with correct type of fuel.
Fuel cock does not open properly?
Apply lubricant to loosen fuel cock lever,
replace if necessary.
Fuel fi lter/lines clogged?
Replace fuel fi lter.
Fuel tank cap breather hole clogged?
Clean or replace fuel tank cap.
Air in fuel line?
Bleed fuel line.