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© 2011 ICS- Blount Inc Specifications and pricing are subject to change without notice. P/N 525747 REV12Sep2012
680GC SERVICE MANUAL
25. DIAGRAMS
Saw Will Not Start
CHECK
POSSIBLE CAUSE
REPAIR
Does the engine crank?
Is there spark?
Is the spark plug firing
properly?
Insure cylinder
compression is above
125 psi
Is the fuel fresh?
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 (25:1)
•
Loose spark plug.
•
If below 125 psi – excess
wear on the piston,
cylinder, rings and/or
improper fuel mixture.
•
Tighten plug and re-test.
•
Replace piston and cylinder.
• Ensure correct fuel/oil mixture
(25:1)
•
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
ground 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