Super Jet Pump Seal Related Symptoms

[Pro-pulsion]

So I have been chasing an issue for some time now and after reading some recent postings about the pump seal I have to wonder if my pump seal has been the culprit the entire time. All mods aside, essentially what I have been experiencing is a symptom similar to bouncing off the rev limiter but a new addition has surfaced as of lately. My coil caved on me recently so I replaced it with a JetManiac Yamasaki coil. The ski ran really well but still seemed to bounce off the limiter a little bit. I did some carb work, tear down, clean and reinstall. The ski seemed to be really good for a while and now back to the limiter-like issue. Also, the new addition is a vibration in around where the pump seal is located. It could be midshaft bearings but it just seems odd that the ski will run mint for about 20-30 minutes, then the gremlins start acting up.

My question is, is it possible that the pump seal is the core to what ails it? My thoughts are that when the seal is out of the water and dried out it tightens up, when back into the lake at the start of the ride it is still tight and all is well. After about 20-30 minutes of being pressurized from the ride, it gets lazy and starts to stretch, voila, enter cavitation gremlins. Does this make sense? It is the original stock seal from '96. I have a new one, just haven't had a chance to install it yet. It may have to be done now though if my suspicions are correct. What do you guys think?

 

[Crab]

Just silicone it in on the inside to rule out an airleak.

 

[Pro-pulsion]

Nah, I would rather change it out since I have a new one. I was just interested to see if what I am experiencing is all due to the seal being toast. Tomorrow morning I plan to change out the seal.

 

[Pro-pulsion]

Yep, the old seal was a mess and compressed to about 2/3 the thickness of a new one, and it was pealing apart. After getting the new one in and taking an hour and a half of ride time today it was very clear that the old seal was the main problem for the issues I was experiencing. No more cavitation, tons of hook up and no more "rev limiter" issues. Good lesson learned, and for 35 bucks to buy a new OEM seal plus an hour of time it was well worth it.