Speedster 215 Supercharged CAVITATION?

[meedz]

I picked up an 07 speedster today from the dealership - supercharger was rebuilt 10 hours ago, and the machine currently has 140 hours.

That said I noticed from a stop it always cavitates and bounces off the redline until it catches speed. Same goes for when you take a good 360 turn and she slows down, that same redline occurs with cavitation until it picks up speed once again.

Dealership states this is normal for the speedster? Is this true? Or is the wear ring / impeller on their way?

Coming from my 2015 GTI PWC I've never had this sort of cavitation.... So not sure if this is normal on a boat?

 

[pete63]

what size speedster? 150?
i mean what are you doing, just full throttle and making it red line? i'm not saying to feather it but you need to do same as a v8 car...
360 the boat will bog down then pick up. but i would say there is some cavitation there, end of the season you can change the wear ring and che the impeller for dings etc.

 

[xintersecty]

I would not just slam it. Ease it up. Most likely they are BSing you and you need to inspect the pump. Slamming it does cause cavitation. Remember you like twice the weight of a jetski

 

[rcnut]

I have a 09 Speedster 150 with a 215 supercharger. I have no cavitation issues going from idle to WOT, she just jumps up on plane and haul's ass. I honestly don't know what the RPM's are doing but it's very steady throughout the process. This is with 2 people in the boat. I haven't done any 360's so I can't comment about that.

 

[Coastiejoe]

Not uncommon for Speedsters to have some cavitation due to the over-all weight of the boat. However, it should not be so bad to be bouncing off the Rev Limiter though.

 

[meedz]

I'll take a video this afternoon to show you - it's got a 30 day warranty so I need to iron out any issues!

Definitely the cavitation just seems so off, it does not feel normal or natural in anyway. Even when she does pick up speed and I go WOT it still bounces off rev limiter.

 

[Coastiejoe]

You either have a bad wear ring or you are sucking air into the jet via the CS..

 

[meedz]

Sorry for the delay, it's been a hectic few days.

Just an update on this while I had some time today, I went out alone and hopped in back - and while doing circles I recorded the CS in operation to see if there was any water.

You'll see in the video droplets of water are formed and fall. Is this a sign that it's leaking?

I will be at it again tomorrow with a buddy driving with greater throttle - i couldn't go very fast alone.

https://vimeo.com/176824161

 

[Coastiejoe]

It is suppose to drip. But not stream water. I'd say yours is ok but drips more than it should just slightly.

Maybe it is me, but the shaft looks like it is at an angle compared to the collar. If so, that is a problem.

Was this engine removed? If so, was it aligned when reinstalled?

 

[meedz]

It is suppose to drip. But not stream water. I'd say yours is ok but drips more than it should just slightly.

Maybe it is me, but the shaft looks like it is at an angle compared to the collar. If so, that is a problem.

Was this engine removed? If so, was it aligned when reinstalled?

I agree with you on the angle - not sure if it's just the angle I took the video or not - I'll take another look today.

The supercharger was rebuild by the dealer last year, does this require the engine be removed?

With the angle being off, what sort of issues does this cause in the long run? Added stress on the shaft?

 

[Coastiejoe]

Engine does not need pulled to rebuild the SC. You may have broken mounts or someone pulled it before and didn't align it.

Alignment is VERY important. Out of alignment you get cavitation, worn wear rings, shaft spline failure, impeller bearing failure, and engine load issues that may create vibrations.

 

[meedz]

So went out again today:

1) while in the back noticed a significant leak from the centre at the rub rail - I guess this is a common problem. Dealer told me they knew about it and fixed it but I guess not. I also found a random strap and a handful (good dozen or two) of rivets in the back. I'm assuming these are from when they rivet the rails?

2) took another video, no "stream" at the carbon seal
However the droplets are faster forming at higher speeds.

3) looked at the alignment, it almost seems as though the shaft is straight but the collar is angled in? What do you think?

https://vimeo.com/176886812

 

[Coastiejoe]

At one point it looks like it all moves when revving up and coming off the Revs. Take a good look at the motor mounts. Should be rock solid. Try to wiggle the engine.

 

[meedz]

At one point it looks like it all moves when revving up and coming off the Revs. Take a good look at the motor mounts. Should be rock solid. Try to wiggle the engine.

Just tried to move it, it's rock solid. It could have just been the way I was holding the camera. It was impossible to keep it stable with the exhaust burning hot and the waves lol!

Either way I've got to go back to the dealer for the leak, I'll mention the angle of the shaft to the collar and see what they say. They'll likely brush me off but worth a shot.