jet rebuild?

[mach1 454]

i have a 1975 20' mach1 with a 454chevy. my question is when i take off from a 5mph zone or a complete stop my boat takes forever to get on plane. it just started doing that one day all of a sudden. before when it was running right it got on plane pretty quick. the pump was just rebuilt at the end of last summer and still looks in good shape. the rpm also shoots up to 5100 RPM at take off and once it gets on to plane its max RPM is 4900RPM. so my question is, what is the deal and what could be wrong?thanx
mach1454

[Lumpy]

Mach1,
Sounds like cavitation to me. Did you by chance install a different grate?

[Lake Lifeguard]

I agree with the cavitation theory. I have to assume that you have already popped the inspection plate off and checked your impellor shaft. If you havent done so then check it out. Even a very small amount of fishing line, weeds, etc can cause significant cavitation. Anything that can cause abnormal turbulance inside of the pump can generate cavitation during accelleration.

[skeepwerkzaz]

My guess is you have a piece of tow rope or some other debris stuck up there, probably way up there. Maybe a rock in your impeller, any strange noises associated? You may also want to tighten down your suction piece bolts, they may be sucking air. Good luck.

[Bense468]

On that note when you pull your inspection cover check the o ring to see if it is shot, or mis-aligned. You can suck air though there also. Good luck.