1987 125 HP Force losing power at WOT

[KeukaBoater]

1987 Force 125 on a 19' Bayliner. Owned it since 1990.

Motor starts and idles fine, but when pulling a skier it noticeably loses power at WOT, seems to fluctuate up and down. Have checked compression, good in all cylinders, have spark in all, just replaced plugs. Over the years I have replaced coil packs, CDI's, and the stator.

Not sure where to start with this new adventure, any suggestions would be greatly appreciated,

 

[Jiggz]

Losing power at WOT while smoothly running at below WOT is an indication of fuel delivery or starvation problem. There is a good possibility the fuel pump maybe leaking or fuel hose or the primer bulb is also sucking in air. For troubleshooting, install a clear fuel filter between the fuel pump and the carb's inlet. It should stay at leas 1/2 full everytime. If not you have fuel delivery problem. If it does stay at least 1/2 full, then it is a carburetion problem. Even a cheap Fram G2 filter will do. This is more for troubleshooting than filtering.

 

[jerryjerry05]

Pull the fuel pump and check the diaphragm.
Jiggz's idea of the inline filter for just testing purposes is good.
But leave it there.
I've found it really helps keep the carbs clean of the tiny buggers that get stuck in the needle.

 

[KeukaBoater]

Thank you for the suggestions, I will see what I come up with. Appreciate the help!

 

[oldboat1]

believe a slipping prop hub can give symptoms like that as well.