omc 5.7 low rpm at wot

[saluscon]

Hello, I have 1990 omc 5.7 in my carver 528. at wot i can only get to 3200 rpm. I have the right prop. I have rebuilt the carb, new ignition and the timing is right. It runs great, shifts well and in idle the engine will rev above 4000 rpm. In gear, at wot, i can only get 3200 rpm. Any suggestion as what can be cause the lack of power?

Joseph

 

[Don S]

Re: omc 5.7 low rpm at wot

List of possible causes of low WOT (Wide Open Throttle) rpm.

In no particular order

Engine Won't Reach Operating RPM. Check

1. Fuel condition. Type and Octane possibly old fuel
2. Propeller pitch or diameter, damaged blades
3. Restricted fuel pickup tube or anti siphon valve Fuel System Test
4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
5. Marine growth on hull and outdrive
6. Wrong gear ratio in outdrive
7. Restricted carburetor air intake (clogged flame arrestor)
8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
9. Poor cylinder compression Compression Test
10. Carburetor defective, or wrong type.
11. Fuel pump pressure and vacuum
12. Boat overloaded, improperly loaded, or improperly trimmed.
13. Engine Overheating
14. Engine timing and ignition system operation
15. Remote control cables and linkage for proper travel to open throttle plates fully.

 

[saluscon]

Re: omc 5.7 low rpm at wot

Thanks Don. Much appreciated.