Morrison MCS25 - Troubleshooting Engine Issues; Engine Not Starting Diagnosis; Low Power and Knocking Solutions

11
Trouble shooting
Engine does not start
What to Check Possible Cause Remedy
Does the engine crank?
YES
NO Faulty recoil starter.
Fluid in the crankcase.
Internal damage.
Return chainsaw to dealer
Good compression?
YES
NO Loose spark plug. Excess wear on cylinder,
piston, rings
Tighten and re-test. Return unit to
dealer
Does the tank contain fresh fuel
of the proper grade?
YES
NO Fuel/mixture incorrect, stale, contami-
nated.
Re-fill with fresh fuel (2-cycle
engine oil and gasoline, as speci-
fied.)
Is fuel visible and moving in the
return line when priming?
YES
NO Check for clogged fuel filter and/or vent. Clear as required. Re-start.
Check the spark plug If the plug is wet, excess fuel may be in the
cylinder
Crank the engine with plug
removed. replace the plug and
restart. (Refer to page 7)
The plug may be fouled or improperly
gapped
Clean and regap the plug to
0.65mm. Restart.
The plug may be damaged internally or of
the wrong size.
Replace the plug with the speci-
fied plug. Restart
Low power output
What to Check Possible Cause Remedy
Is the engine overheating? Operator is overworking the machine. Use lower throttle setting.
Carburettor mixture is too lean. Return chainsaw to dealer.
Improper fuel ratio. Re-fill with fresh fuel of the correct
mixture (2-cycle engine oil and
gasoline, in specified ratio Page 5.)
Fan cover, cylinder fins dirty or damaged. Clean, repair or replace as neces-
sary.
Carbon deposits on piston or in the muffler. Decarbonize.
Engine is rough at all speeds. Clogged air cleaner element. Service the air cleaner.
May also have black smoke and/ Loose or damaged spark plug. Tighten or replace.
or unburned fuel at the exhaust. Air leakage or clogged fuel line. Repair or replace filter and/or fuel
line.
Water in the fuel. Drain the fuel replace the fuel with
a fresh mix.
Piston seizure. Return chainsaw to dealer.
Faulty carburettor and/or diaphragm. Return chainsaw to dealer.
Engine is knocking. Overheating condition. Idle engine until cool; find reason
for overheating.
Improper fuel. Check fuel octane rating; check
for presence of alcohol in the fuel.
Refuel as necessary.
Carbon deposits in the combustion
chamber.
Decarbonize