Will this cause Cavitation? Pump Vein Damage

[n-mod]

I have some cavitation in my seadoo sportster. The impeller is in great shape with a new wear ring. So I am looking at other causes. I will test the accordion rubber bellow next time i'm out to make sure their is enough pressure on the carbon seal.

Right now I have the impeller out and see some pretty serious vein damage. Will this cause much cavitation? And does anyone know a way to repair them? I was thinking I might just sharpen them up, or maybe use some epoxy and see if it holds. 10 vein pumps are very expensive and I'm not sure if less veins will work well.

Look at the photos and tell me what you think.

 

[KK40384]

That looks toast to me. That looks like the older pump that wasn't made of aluminum. The early 4 Tec models had them and there was some issues with them flexing under throttle and causing cavitation in the SC models. You can always upgrade to the newer metal pump if the wallet allows.

 

[n-mod]

The problem is my wallet doesn't really allow it, at least right now. I am going to sharpen the vein edges and see if that makes a difference. My model is a 2004 with the non-supercharged 155hp engine.

Has anyone else had experience with vein damage causing cavitation? I don't want to replace it if it won't make much of a difference.

 

[Coastiejoe]

Though the veins are screwed up for sure. As long as they are not twisted, bent or leaning (meaning they are still nice and straight) I don't think the damage we are seeing would give you cavitation.

I would definitely do the wire tie boot trick to ensure you are not sucking air through the carbon seal.

 

[speedster98]

Check that pump seal, I see some wet in pic 2. If you have a leaking pump seal you will seize it and have no choice but to replace.

 

[KK40384]

The problem is my wallet doesn't really allow it, at least right now. I am going to sharpen the vein edges and see if that makes a difference. My model is a 2004 with the non-supercharged 155hp engine.

Has anyone else had experience with vein damage causing cavitation? I don't want to replace it if it won't make much of a difference.

In that case just take a file to them and get them straight again. I see a few of them are folded on one side. No big deal if you can get them straight again. I don't think any epoxy or the like will hang on once that impeller starts spinning full steam. Also check the carbon seal like you mentioned above.

 

[n-mod]

Though the veins are screwed up for sure. As long as they are not twisted, bent or leaning (meaning they are still nice and straight) I don't think the damage we are seeing would give you cavitation.

That is exactly what I was thinking. But now I just read this on impros site:
"Pump vanes with chunks even the size of half a dime will shave substantial performance and create a spinning effect no matter how well the pump is sealed, or which impeller is installed. If you're noticing excessive cavitation, then they need to be repaired."
http://impros.com/store/index.php/services/pump-vane-repair.html

So now I'm thinking this could be a big part of the issue.

Check that pump seal, I see some wet in pic 2. If you have a leaking pump seal you will seize it and have no choice but to replace.

The seal is good, that wetness is the pump oil running down the walls when I pulled the pump cone.

 

[n-mod]

I think I found my problem. Looks like my new wear ring is garbage. The clearance on each side was almost 1mm. I just put a new WSM one in and it looks a lot better. I will test it out see how it goes. Also I tried some marine epoxy on the vanes and it looks like it might actually hold, so maybe I can repair them. I will check after this first run to see if the pieces I made are gone.

 

[Coastiejoe]

I think I found my problem. Looks like my new wear ring is garbage. The clearance on each side was almost 1mm. I just put a new WSM one in and it looks a lot better. I will test it out see how it goes. Also I tried some marine epoxy on the vanes and it looks like it might actually hold, so maybe I can repair them. I will check after this first run to see if the pieces I made are gone.

Best of luck to you.

General rule is the thickness of a dime or less is acceptable for wear rings.

 

[n-mod]

Good news! The WSM Wear ring fixed the problems. I tested with 2 people in the boat and experienced zero cavitation! Also the epoxy vane did hold up so maybe if I ever have it apart in the future I will do the other remaining 9.

 

[KK40384]

Good stuff. Glad it all worked out with little damage to the wallet.

 

[Coastiejoe]

Congrats on the fix...