Max speed 7mph

[Seadoo Brian]

96 sportster, replaced wear ring, o rings, oil, propeller in good shape, new foam gasket between drive and hull. Drive linkage works, motor revs, but can only do 7mph. Any ideas on what to look at, just purchased this boat, first boat.....

 

[Seadoo Brian]

96 sportster, replaced wear ring, o rings, oil, propeller in good shape, new foam gasket between drive and hull. Drive linkage works, motor revs, but can only do 7mph. Any ideas on what to look at, just purchased this boat, first boat.....

 

[Seadoo Brian]

I just noticed that a clear line is hanging loose, looks like it goes into this fitting on the exhaust?

 

[JeremyD615]

Here’s a picture of how that line is routed on my 717 ski. It should be the same on the boat...

 

[Sportster-2001-951C-Stock]

That fitting looks like a water injection port. Should be shown in the jetski documentation which you should be following.

If only 7MPH, I guess that's after unstrapping it from the trailer? Sorta sounds like PTO splines are worn out, but you didn't elaborate on how many RPM it's producing, I assume near ~7,000 or so.

 

[Seadoo Brian]

No tach on this model, motor was reving and taking the throttle

 

[Seadoo Brian]

Can you explain what the water Injection port does?

 

[Sportster-2001-951C-Stock]

Water injection keeps the exhaust system from overheating.

When you launch, you're not taking the trailer along for the ride, right?

 

[Sportster-2001-951C-Stock]

No tach on this model, motor was reving and taking the throttle

Well that's good! My guess is torque is not being transferred from the engine to the impeller due to the drive shaft is not coupled by the splines.

 

[Seadoo Brian]

I will pull drive off hull and look at splines where it connects to impeller shaft. What about the side of the shaft that goes I to motor? Do u know how that is coupled to moror?

 

[Seadoo Brian]

Water injection keeps the exhaust system from overheating.

When you launch, you're not taking the trailer along for the ride, right?

It sure felt like it

 

[Sportster-2001-951C-Stock]

I will pull drive off hull and look at splines where it connects to impeller shaft. What about the side of the shaft that goes I to motor? Do u know how that is coupled to moror?

I think it's at the motor end of the shaft, specifically the PTO splines. You probably need to replace that and maybe the shaft too.

 

[Sportster-2001-951C-Stock]

If someone has replaced or moved the engine, they may have not realigned it with the jet pump using the engine alignment fixture. Misalignment is almost sure to wear the splines faster than normal but they do wear out eventually.

The engine alignment fixture is one of the service tools for jetskis.

 

[Sportster-2001-951C-Stock]

One more thing you need to know is before removing the jet pump is the tension of the stainless ring against the rubber bellows holding the carbon ring needs to be released before removing the jet pump. Push/slide the stainless ring aftward towards the jet jump to expose the retaining clip, remove this clip from the groove in the drive shaft. This will allow you to pull the drive shaft out of the through hull fitting.

You'll probably have to remove the driveshaft grease boot as well, there are two clamps, I'd remove the large diameter one using pliers, it can be replaced using a nylon tie wrap.

 

[Seadoo Brian]

Took drive shaft out, carbon ring has a lot of play,what do you think about the shaft splines? The motor side is pictured

 

[Seadoo Brian]

Also, should a little rubber stop be pushed into each end of the drive shaft?
Also help me understand how the carbon ring being worn out can cause cavitation, still don't totally understand how this works.

 

[Sportster-2001-951C-Stock]

The shaft doesn't look terrible. Wonder if the inside splines of PTO are worn enough to slip. I didn't realize the PTO end of shaft has the hour-glass shape, are both ends like that?

As far as I know yes, both ends have a rubber bumper inserted into the shaft ends.

 

[mikidymac]

To me the splines look perfect. Even if just the PTO was damaged it would leave marks on the driveshaft from it spinning.

The carbon ring can cause cavitation because it lets air from the engine compartment get sucked into the pump. If you are moving air, you aren't moving water.

 

[Sportster-2001-951C-Stock]

Show us the carbon ring, was it leaking a lot of water there? Inside of mine is egg shaped a little, I rotated it 90 degrees to attempt getting more life, doesn't seem to leak air.

 

[mikidymac]

The very few I have seen actually suck air, it was the boot that fixed it, the actual carbon ring still looked ok. On the flip side, the ones leaking water the carbon ring was in really bad shape.

 

[Sportster-2001-951C-Stock]

The shaft doesn't look terrible. Wonder if the inside splines of PTO are worn enough to slip. I didn't realize the PTO end of shaft has the hour-glass shape, are both ends like that?

As far as I know yes, both ends have a rubber bumper inserted into the shaft ends.

Oh yes, it would have that shape. You do need both rubber bumpers, look inside PTO to see if one's still in there.

 

[Sportster-2001-951C-Stock]

The very few I have seen actually suck air, it was the boot that fixed it, the actual carbon ring still looked ok. On the flip side, the ones leaking water the carbon ring was in really bad shape.

Yeah, that makes sense.

 

[Seadoo Brian]

The shaft doesn't look terrible. Wonder if the inside splines of PTO are worn enough to slip. I didn't realize the PTO end of shaft has the hour-glass shape, are both ends like that?

As far as I know yes, both ends have a rubber bumper inserted into the shaft ends.

Both sides are hour glass shape

 

[Seadoo Brian]

I would guess the carbon ring should be almost tight as it sits on the shoulder of the shaft?

 

[Seadoo Brian]

What's the best place to order a rebuild kit for the bellows and carbon ring, etc.