125 won't plane

[heycookieman]

Ok this may be long but I'll try and give you all the info I can. I have a 1988 125 force on a 21' c/c bayliner boat.The prop is a 13"X21p. I have 125 psi in each cyl. Carbs are rebuilt and clean. The boat would get to 16-18 mph and 2000 rpm's no higher and wouldn't plane till my wife went to the front of the boat and sat down. After about 2-3 min. the boat hit 36 mph and only 3000 rpm's.I don't know if it's the prop or maybe the carbs or the reeds. The motor it's self does not have a lot of hours on it.Thanks

 

[pnwboat]

Re: 125 won't plain

Re: 125 won't plain

If the engine is functioning normally, it sounds like you're over propped. Somewhere around a 17 pitch would probably be closer to what you need. Only way to be sure would be testing props w/different pitches.

 

[heycookieman]

Re: 125 won't plane

Thanks PNW. That's what I thought. Just bought a 17

 

[pnwboat]

Re: 125 won't plane

I have a 19' open bow Bayliner w/1988 125HP. I'm using a 17 pitch which gives me 5300 RPM's. and 43 MPH. I tried a 19 pitch cupped but could only get about 4700 RPM's and took longer to plane and about 39 MPH. Based on my experience, I would guess that the 21 is way too much pitch. I think you'll see much better performance with the 17 pitch prop.

 

[john from md]

Re: 125 won't plane

Your boat would get on a plane faster and handle better if you add a set of Smart Tabs to it. They work much better than Dole fins or the others that screw on the cav plate.

John

 

[heycookieman]

Re: 125 won't plane

Thanks again PNW and John I'll look in to that thanks guys.