Generac — GENERAC

A Generac service procedure — check it applies to your exact model before use.

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Procedure

1. 1. 0-10% Cylinder is good
2. 2. 10-30% there may be a problem
3. 3. 30-100% Cylinder requires repair
4. Things Which Affect Both Cylinders:
5. 1. Carburetion
6. 2. Crankcase vacuum
7. 3. Ignition timing
8. a. A partially sheared flywheel key will effect ignition timing
9. and engine performance.
10. Things Which Affect One Cylinder:
11. 1. Spark plug
12. a. A fouled spark plug may indicate that carburetor is out
13. of adjustment.
14. 2. Leak in spark plug wire
15. 3. Head gasket

Source: manual:0C1103A.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.