Troubleshooting list for GTs. Let me know and I can send you the page it references.
Symptom: Engine is running on one cylinder
(1) Is ignition coil air gap adjusted properly? See “Ignition Armature Air Gap Adjustment” on page 82.
No - Adjust air gap to specification.
Yes - Go to next step.
(2) Are spark plugs loose/dirty?
Yes - Clean or replace and tighten to specifications.
No - Go to next step.
(3) Is magneto kill circuit grounded - shorted? See “Ignition Circuit Diagnosis” on page 276.
Yes - Repair as needed.
No - Go to next step.
(4) Do valve tappets need adjustment? See “Valve Inspection and Repair” on page 95.
Yes - See “Valve Inspection and Repair” on page 95.
No - Go to next step.
(5) Does engine lack compression? See “Compression Test” on page 77.
Yes - Check valves, pistons and rings.
No - Go to next step.
(6) Are cylinder head bolts loose? See “Cylinder Head Removal and Installation” on page 92.
Yes - Tighten to specification.
No - Go to next step.
(7) Is head gasket defective?
Yes - Replace. See “Cylinder Head Removal and Installation” on page 92.
No - Go to next step.
(8) Are valves and/or valve seats burned or are valve seats loose? See “Valve Inspection and Repair” on page 95.
Yes - Repair or replace as needed.
No - Go to next step.
(9) Is cylinder head warped? See “Cylinder Head Inspection and Repair” on page 95.
Yes - Replace. See “Cylinder Head Removal and Installation” on page 92.
No - Go to next step.
(10) Is camshaft worn?
Yes - See repair section.
No - Go to next
(11) Is connecting rod broken? See “Connecting Rod Inspection” on page 98.
Yes - See “Piston, Rings and Rod Removal and Installation” on page 97.
No - Go to next step.
(12) Are cylinder bore or rings worn? See “Piston Inspection” on page 98 and “Cylinder Bore Inspection” on page 101.
Yes - Repair or replace as needed.
