Service manual

TROUBLESHOOTING SERVICE MANUAL NUMBER 26
Page 1C-18 90-861329--1 MARCH 1999
Engine Runs Poorly At Idle
Cause Special Information
Clogged flame arrestor
Improper idle fuel mixture adjustment
Problem in ignition system causing the
engine to run rough
Idle mixture screw adjusted incorrectly
Engine floods at idle
Bad needle and seat
Engine floods at idle
Incorrect float level drop
If carburetor (2 barrel only) has a solid
needle, replace with a spring loaded
needle
Moisture on ignition components Cap or spark plug wires arcing
Water in fuel
Low grade or stale fuel
Incorrect ignition timing
Automatic choke
Spark plugs Fouled, burned, cracked porcelain
Spark plug wires Insulation breakdown, wires broken
Defective coil
Cracked or dirty distributor cap
Incorrect float level
Dirty carburetor
Vacuum leak Leak at manifold or carburetor base
Incorrect fuel pump pressure
Too low - can’t supply the carburetor
Too high - unseats the needle and seat
Low compression Also check for blown head gasket
Loose or worn distributor Timing changes
Water leaking into cylinders
Head gasket, exhaust manifold, cracked
head or valve seat
Loose or broken engine mounts
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