© 2011 ICS | Blount, Inc. Specifications and pricing are subject to change without notice. P/N 550416 REV06012011
660GC SERVICE MANUAL
75
24
This section provides several flowcharts to aid diagnosing common problems.
CHECK
POSSIBLE CAUSE
REPAIR
The engine runs rough at
all speeds.
The engine is overheating.
• Operator is overworking
the saw.
• Carburetor mixture is
too lean.
• Incorrect fuel/oil ratio.
• Flywheel fins are clogged.
• Air deflector is missing.
• Cylinder fins are clogged.
Poor acceleration.
• Dirty or clogged air filter.
• Clogged fuel filter.
• Incorrect carburetor tune.
• Plugged tank breather.
• Blocked pulse tube.
Uneven idle or engine
may “run away”.
• Air leak at intake boot,
cylinder gasket, or
crankcase gasket.
• Faulty carburetor
diaphragm.
Diamond chain
moves at idle.
• Idle speed too high.
• Broken clutch spring.
Excessive vibration.
YES
• Damaged shock absorber.
• Damaged or broken
flywheel fins.
• Bent crankshaft.
• Replace shock absorbers.
• Replace flywheel.
• Replace crankshaft.
• Adjust idle speed.
• Replace clutch spring.
YES
• Inspect air intake boot.
• Pressure test crankcase.
• Replace carburetor.
YES
• Clean or replace the air filter.
• Replace fuel filter.
• See Carburetor Tuning section.
• Repair or replace fuel tank
breather.
• Replace pulse tube.
YES
• See Operator’s Manual.
• See Carburetor Tuning section.
• See Saw Specifications section.
• Clean flywheel fins with
wire brush.
• See Starter Cover section.
• Clean cylinder fins.
YES
• Dirty or clogged air filter.
• Water has been ingested.
• Loose or dirty spark plug.
• Clean or replace the air filter.
• Inspect air intake system for water.
• Inspect fuel system for water.
• Tighten, clean, or replace
spark plug.
YES
A dirty air filter is the #1 reason for engine problems.
24. DIAGRAMS
