Engine - Stihl MS 231 Manual

3.7

Engine

Always check and, if necessary,
repair the following parts before
looking for faults on the engine:
- Air filter
- Fuel system
- Carburetor
- Ignition system
Condition
Engine does not start easily, stalls
at idle speed, but operates normally
at full throttle
Engine does not deliver full power
or runs erratically
Engine overheating
18
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Cause
Oil seals in engine damaged
Engine pan leaking or
damaged (cracks)
Intake manifold damaged / bore
blocked
Piston rings worn or broken
Muffler / spark arresting screen
carbonized
Air filter dirty
Fuel hose kinked or torn
Intake manifold damaged / bore
blocked
Insufficient cylinder cooling. Air
inlets in fan housing blocked or
cooling fins on cylinder very dirty
Air inlet in fan housing dirty
Remedy
Replace the oil seals
Inspect engine pan, re-seal or
replace if necessary.
Clean bore or install new manifold.
Fit new piston rings
Clean the muffler (inlet and
exhaust), replace spark arresting
screen, replace muffler if necessary
Clean or replace air filter
Fit new hose or position it free from
kinks
Clean bore or install new manifold.
Thoroughly clean all cooling air
openings and the cylinder fins
Clean air inlet on fan housing
MS 231, MS 231 C, MS 251, MS 251 C