633GC SHOP MANUAL
68
Copyright © 2005 ICS, Blount Inc.
Saw Will Not Start
CHECK
POSSIBLE CAUSE
REPAIR
Does the engine crank?
Is there spark?
Is the spark plug firing
properly?
Check cylinder
compression
Is the fuel fresh?
Is the fuel mixed 25:
Is the fuel reaching the
carburetor?
Is too much fuel
reaching the
carburetor?
Is the flywheel key
sheared?
•
Loose flywheel
•
Replace key and reinstall flywheel
•
Carburetor is tuned
incorrectly
•
Plugged fuel tank breather
•
Refer to Carburetor Tuning
section
•
Repair or replace fuel tank
breather
•
Clogged fuel filter
•
Damaged fuel line
•
Damaged pulse tube
•
Plugged fuel tank
breather
•
Replace fuel filter
•
Replace fuel line
•
Replace pulse tube
•
Repair or replace fuel tank
breather
•
Fuel is old, varnished, or
contaminated
•
Empty tank and re-fill with fresh
fuel of the correct mixture (50:)
•
Loose spark plug
•
If below 25 psi – excess
wear on the piston,
cylinder, rings
•
Tighten plug and re-test
•
Replace piston and cylinder
•
Plug is soaked with fuel
•
The plug is fouled or
gapped improperly
•
Plug is internally faulty or
the wrong type
•
Dry plug, expel excess fuel from
cylinder and crankcase
•
Clean and re-gap the plug to
0.020 inch (0.05 mm)
•
Replace with the correct plug –
See Spark Plug Reference Guide
•
The ignition switch is
“OFF”
•
Faulty ignition ground
•
Faulty spark plug lead
•
Faulty ignition coil
•
Move switch to “ON” and re-test
•
Tighten connections or replace
round wire
•
Repair or replace spark plug lead
•
Replace ignition coil
•
Dirty or broken recoil
starter
•
Internal damage
•
Clean, rebuild or replace the recoil
starter
•
Inspect for internal damage such
as seized piston
YES
YES
YES
YES
YES
YES
NO
YES
YES
NO
NO
NO
NO
NO
NO
25. DIAGRAMS
