Engine Vibrates Excessively

We listed possible causes of the problem engine vibrates excessively:

1. Propeller out of balance or out of track
2. Bent crankshaft
3. Unequal valve clearance
4. Defective spark plugs
5. Engine loose on mount
6. Propeller hub nut loose
7. Carburetor icing
8. Incorrect carburetor setting
9. Engine too cold
10. Improper ignition timing
11. Worn dynamic dampner bushings or pins