97 challenger slippage ?

[jcon]

I have a 97 challenger 787 with a fresh rebuild on the motor. Don't know the whole boat history, but occasionally when I first get out on the water I and slowly start to bring up the throttle the rpm's climb but the boat goes no faster. After tooling around for 5-10 min it's all good. If it was a car I would say transmission is slipping or clutch is bad ? Any suggestions ? Only 2nd season with the boat so not yet a seasoned vet.

 

[Lumps]

can you please explain a little more? when are accelerating do you hear a pulsing noise, like it sounds like its hitting the rev limiter (the sound is hard to describe)? these boats have no gears or clutch etc to slip. the engine is straight out the back to the prop. but they can cavitate. typically this is caused by accelerating too fast or problems with the prop. I understand that air leaking into the pump can also cause issues with acceleration.

when you give it throttle does it go to max rpms? I ask because I don't know if any of this stuff would resolve its self after 5-10 minutes.

 

[Ankeneyou]

Check wear rings in the jet pump. I guarantee it's out of tolerance or just gone. You should barely see any light if you shine a flashlight in the intake and look through the pump.

They say width of a dime is the max, but I think that's too much especially on a single engine boat.

 

[jcon]

Check wear rings in the jet pump. I guarantee it's out of tolerance or just gone. You should barely see any light if you shine a flashlight in the intake and look through the pump.

They say width of a dime is the max, but I think that's too much especially on a single engine boat.

I just had my mechanic install new wear rings this season is there something he could have gotten wrong ?

 

[jcon]

can you please explain a little more? when are accelerating do you hear a pulsing noise, like it sounds like its hitting the rev limiter (the sound is hard to describe)? these boats have no gears or clutch etc to slip. the engine is straight out the back to the prop. but they can cavitate. typically this is caused by accelerating too fast or problems with the prop. I understand that air leaking into the pump can also cause issues with acceleration.

when you give it throttle does it go to max rpms? I ask because I don't know if any of this stuff would resolve its self after 5-10 minutes.

Yes when you give it throttle it goes to max rpm quickly I was unsure if the prop is on the shaft with pins or set screws or how that end really works. This is my first jet type boat. We can have a great 4 hour run and no issues. This has only happened 3 times in 6 outings and it always fixes it self. I just know that one of these times the underlying issue will surface and it will be done. I did notice it may be when the boat has 2 passengers in the rear and not spread out to the bow ? Just trying to give as much info as I can come up with

 

[Lumps]

The prop is held with spines (is that the right term). Assuming you have the same as in the 98 version. Maybe you are a little out of tune and it works better when warm