Replacing Wear Rings and Impeller questions

[kappachampion]

Hey guys,

I disassembled the jet pumps on my 97 speedster today because I was having some cavitation issues (high RPMs no thrust). The wear rings have some wear, but I'm not sure how to tell if it is irregular. Some groves seem to be deep (maybe a mm or 2). There is a knick in the wear ring in one location and the impellers have significant damage along the leading edge (I think my brother got into some rocks). There are several dings along the edge, some being several mm long and a couple mm deep.

Do you think these can be repaired or should I just replace them? Anyone have any idea how much repairs cost vs replacements? Is there a better impeller than stock that I should just upgrade to?

Also, while I was down there I noticed, the white plastic "driveshaft shield" (don't know what it is really called) was missing from one engine. I plan on replacing this but was curious if it could be contributing to the cavitation issue.

I also still have a studder in my throttle at about 1/3 throttle. it goes past it just fine but if I pause there the RPMs will drop. Any ideas?

Some other random questions:
I need to replace mu scupper valve any suggestions of the rubber vs pingpong ball ones?
I need to repaint the steering nozzle on one of my jet pumps (it is starting to corrode) will standard paint work fine, or is there paint for marine use?

Anyways, thanks for the help. I'll keep researching other cavitation problems and things I can check.

 

[shamski]

Post some pics of the wear ring and impeller and I am sure someone can comment on it. I had a post on my issues a while back, and ended up replacing wear ring and getting a refurb impeller (SBT). You may be able to find someone local to repair the impeller, but they really need to know what they are doing. Parts for me were approx $60CDN for wear ring, and $25US for refurb stock impeller (+ shipping which to Canada was costly - still way cheaper than new); you just need to send them your old impeller. It is a good DIY project if you take your time. If you go the "stealers" to get it done, it will be 4 - 5x your parts cost and waiting for them to fit you in .

Have to let other comment on the aftermarket impellers - solas, etc.

 

[roneagan@cfl.rr.com]

Don't worry about the shaft covers, they are supose to prevent a rope or other material from wraping around the shaft.. I don't have either of mine anymore and it makes no difference.. While you have the pumps out change the seal on the shaft carrier bearing thats on the hose with clamps where it comes through the hull.. If these are not good it may cause cavitation, it is refered to as the carbon seal..