1989 OMC Four Winns losing RPM's???

[4WinnsCobra89]

So after my mechanic replaced the intermediate cable, greased and inspected Everything and we replaced all gaskets and o rings in the outdrive, I take the boat out, starts and shifts great, idles perfect, I get out of the no wake zone and open her up. Runs great for about 5 minutes and then engine sounds like I slowed it down but I didn;t touch a thing. I got up to about 4500 RPM's before it did this. Also lost about 400 RPM's when this happened and then it speeds up again and then repeats itself. I had to turn around and "limp" into the dock for a 3rd time this season. Anyone have any ideas what might cause this?

 

[mcleaves]

Re: 1989 OMC Four Winns losing RPM's???

Helps to know what yourt setup is. Engine?

 

[4WinnsCobra89]

Re: 1989 OMC Four Winns losing RPM's???

Sorry...It's a 2.3 liter 4 cylinder GM motor with an OMC outdrive.

 

[Bondo]

Re: 1989 OMC Four Winns losing RPM's???

Ayuh,... Water, or Crud in the fuel, or fuel system...

 

[4WinnsCobra89]

Re: 1989 OMC Four Winns losing RPM's???

Thanks Bondo...It was water in the fuel. I put dry-gas in the tank, changed the spark plugs, and changed the fuel/water seperator. Runs like a champ,