Boat vibration and can't go pass 25mph

[Brianrph99]

Hello guys, I am a newbie. Just got this 2004 Seadoo sportster 4 tec. I took it out and the boat vibrates at idle and as I increase the throttle, it still vibrates bad. The vibration goes away when I turn the steering at certain position, but randomly then it comes back. The boat can't go pass 25 mph and the rpm goes way up to 7000. I took the pump off and nothing at the pump or shaft. Check the wearing, seem to be in good shape, only a minor score. Impeller has a few small nicks here and there but should not affect the vibration. It seem like cavitation, randomly the the vibration goes away and the boat would speed up as normal for 5 secs then bog down again. It acts like some geer slipping or something. I also check the shaft gears and impeller gears are fine to me. Have not check the pump bearing since I don't have the impeller remover tool. I turn the impeller and play with it a little bit and nothing grinding inside and no free play as I push back and forth.

Compression for all 3 cyl at 180.

At this point I am stuck and need your expert advice. Any opinion is greatly appreciated. Thanks so much in advance.

Brian

 

[kwiktsi]

Hello guys, I am a newbie. Just got this 2004 Seadoo sportster 4 tec. I took it out and the boat vibrates at idle and as I increase the throttle, it still vibrates bad. The vibration goes away when I turn the steering at certain position, but randomly then it comes back. The boat can't go pass 25 mph and the rpm goes way up to 7000. I took the pump off and nothing at the pump or shaft. Check the wearing, seem to be in good shape, only a minor score. Impeller has a few small nicks here and there but should not affect the vibration. It seem like cavitation, randomly the the vibration goes away and the boat would speed up as normal for 5 secs then bog down again. It acts like some geer slipping or something. I also check the shaft gears and impeller gears are fine to me. Have not check the pump bearing since I don't have the impeller remover tool. I turn the impeller and play with it a little bit and nothing grinding inside and no free play as I push back and forth.

Compression for all 3 cyl at 180.

At this point I am stuck and need your expert advice. Any opinion is greatly appreciated. Thanks so much in advance.

Brian

I had a piece of a stick lodged between my impeller blades that caused exactly what you describe. I looked it over top to bottom and couldn't find anything until I removed the impeller and saw it there. The way the blades overlap, it was stuck in a spot that was hidden from both front and back when I was looking for it. Maybe you could use a small mirror to look between the blades from the outside since you don't have an impeller tool?

 

[Brianrph99]

I had a piece of a stick lodged between my impeller blades that caused exactly what you describe. I looked it over top to bottom and couldn't find anything until I removed the impeller and saw it there. The way the blades overlap, it was stuck in a spot that was hidden from both front and back when I was looking for it. Maybe you could use a small mirror to look between the blades from the outside since you don't have an impeller tool?

Yes, look all over and nothing. I heard that a bad spark plug can do this? Is this the possibility? Thanks

 

[kwiktsi]

Yes, look all over and nothing. I heard that a bad spark plug can do this? Is this the possibility? Thanks

You said it revs to 7000 rpm's but only goes ~25mph, doubtful it's a plug. If it were vibrating and running slow due to a dead cylinder/misfire, it would not be revving to 7000, and if it did, it would have the speed to match the RPM. The fact that it is revving with no speed is a problem in the pump assembly somewhere.

 

[Brianrph99]

I would say the rpm jumps to 7000 fluctuate. Pulled sparks plugs and looks good, no sign of fouling, may the #2 cyl little wet. I also noticed that the bucket does not lock in when in forward. At this point should I change the wearing? What would cause the vibration that bad? Bent shaft? I look at the shaft and nothing unusual. Anyone else has any idea?

 

[Seadoobuddy]

If the bucket is not fully up then it could hinder your forward speed.
The boat will want to go forward and reverse at same time.
It might also cause the boat to shake at 7K RPMs

 

[Brianrph99]

If the bucket is not fully up then it could hinder your forward speed.
The boat will want to go forward and reverse at same time.
It might also cause the boat to shake at 7K RPMs

It is fully up and the boat shake at idle and high speed.

 

[Seadoobuddy]

It is fully up and the boat shake at idle and high speed.

OH OK, you said it doesn't lock in when in forward so I thought it was dropping down.

 

[Coastiejoe]

Sounds like an impeller issue to me. Your engine is getting good RPMs but you are not really going anywhere. I am think that a blade is bent which will create everything you explain. Vibration and no speed.

 

[devonte007]

I agree with coastiejoe, I think it is time to take apart your propulsion system and do a close inspection.

 

[Coastiejoe]

The Knicks can cause some of your complaints but a bent impeller can cause all of your issues.

It will literally push the water back and forth a bit causing near normal RPMs but no real thrust. If one impeller is bent that is enough to cause serious performance issues.

I think it I worth taking a look at it. Might be able to see it through the intake if it is bad enough.