Low Power and Uneven Running

We listed possible causes of the problem low power and uneven running:

1. Mixture too rich or too lean
2. Leaks in induction system
3. Defective or fouled spark plugs and loose plug connections
4. Improper fuel grades
5. Wet or defective ignition wiring
6. Engine overheating
7. Defective magneto breaker points
8. Dirty or broken carbon brushes in magneto
9. Improper valve and/or ignition timing
10. Propeller out of track, or hub nut loose
11. Carburetor heat control malfunction
12. Cracked engine mount or loose mount bolts
13. Foreign matter in induction system or fuel lines
14. Incorrectly adjusted carburetor control linkage
15. Fuel feed valve leaking or not operating properly
16. Warped or burned valves or valve seats
17. Broken valve springs
18. Worn or sticking pistons or cylinders
19. Cracked pistons or cylinders
20. Bent pushrods
21. Cylinder gaskets blown
22. Magneto ground wire loose and grounding
23. Carburetor icing
24. Fluctuating fuel pressure
25. Defective rocker arms or bearings
26. Defective valve guides
27. Bent crankshaft
28. Crosswind on propeller during ground operation
29. Spark plug wires crossed