Engine - Stihl 064 Service Manual

STIHL 064, 066

Engine

2.2
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
Cause
Oil seals in crankcase
leaking
Manifold leaking
Cylinder base gasket
leaking
Crankcase damaged (cracks)
Secondary air seepage
through poorly mounted
or faulty manifold
Piston rings leaking
or broken
Muffler carbonized
Insufficient cylinder
cooling. Air inlets in
fan housing blocked or
cooling fins on cylinder
very dirty
Intake air preheating
being used at too high
an outside temperature
Remedy
Replace oil seals
Seal or replace manifold
Replace gasket
Replace crankcase
Mount manifold correctly or
replace
Fit new piston rings
Clean muffler (inlet and
exhaust), replace spark
arrestor screen (if fitted)
Thoroughly clean all cooling
air openings
Remove intake air preheating
components; close rotary
shutter
10