Help - Loss of Power??????

[masoptions]

I have a '98 volvo penta IO w/5.7 engine (carborator) on a 23' Wellcraft. When the boat gets to about 3k rpm (the point where it starts to plane) the engine lugs down, i can't get any more rpm/power and white steam/exhaust pours out the back! (ran 100% fine till Saturday afternoon when this started)



This happened to me once before about a year ago but I changed the prop to get more max RPM (3600 -> 4800) and it solved the problem (at least i thougt it did).



This is a newly re-built engine and I am at my wits end trying to figure out what the heck is going on.



Thoughts?

 

[Don S]

Re: Help - Loss of Power??????

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.