Cavitation in 99 gtx

[Wickedplastikman]

Hi everyone! My first post here. I’m new to pwc’s and I picked up a 99 and a 97 gtx. Both are showing some cavitation issues. Sort of like the ”slipping clutch” feeling. I’m going to start with the 99. I bought a new carbon seal and am in the middle of replacing it. Pulled off the jet pump and it looks like the previous owner shattered a prop or something and took out some plastic. I’m not sure if this would cause any issues. Checked my wear ring and the clearance is tight and it seems decent. I also noticed a decent ding on the leading edge of my prop. Not sure if that’s an issue. I’ll attach some pics and see what you guys think.

Now as far as I’ve researched, it seems like cavitation is going to come from either the carbon seal, wear ring, or ride plate. Not sure if I’m missing anything else.

 

[GGuillot]

That wedge has enough damage that it could be causing the cavitation problem. Enough previous damage was done to require a replacement SS prop and new wear ring, that's apparent. Even replacing the wedge, I'd be concerned of the damage still left behind on the hull. Just me, but chunks of gelcoat missing digging into the fiberglass would make me remove the pump to hull plate, the wedge, and the bottom rideplate with the grate out to do a repair job. You'd need to get the rideplate off anyway to get the wedge out BTW.

 

[mikidymac]

The pump shoe can be a total pain to remove and will probably break coming out. You will have to order a new pump shoe and if you get the old one off make sure you save and mark the location of every shim behind it as that is the basis for aligning your engine. IF you loose them or mix them up it will be a nightmare to get it back in alignment.

The easy and cheap fix is to get some marinetex epoxy and patch, repair and sand smooth the damage.

 

[SabrToothSqrl]

Look for a Delrin wear ring. I get them from OSD. They are the same material all the way through, so if you suck up a rock and get it unstuck, the ring doesn't immediately disintegrate and become useless...

 

[Wickedplastikman]

Uh oh. I had already removed the pump to hull plate a couple weeks ago. I was taking in water from there and removed it to seal it up better. I didn’t pay any attention to shims or engine alignment. It didn’t seem like anything got adjusted there. It just bolted right up so that’s what I did. I’ve run the ski since then and didn’t notice any vibration or anything. Is this something I need to be concerned with? It had the cavitation issue before I took it apart also.

The epoxy repair job sounds like something to do over the winter.

 

[mikidymac]

You will end up eating the splines on the driveshaft, engine PTO and impeller.

I have no clue how the factory set the shimming of the Shoe but that is what the entire driveline alignment is based on. I had a cousin who's father in law removed the shoe and all the shims to paint a ski and it took me about 3-4 hours of messing with the alignment tool to get it close enough to shim and RTV in then another hour to get the engine aligned.