Replaced wear ring, now cavitation

[tawood]

I replaced the wear ring (I probably shouldn't have, because the last one was in good shape, but I had the pump apart replacing bearings, so...) and now the boat cavitates pretty bad.
I just took the pump back off and can not see anything out of the ordinary: wear ring looks fine, impeller looks fine, pump turns fine, impeller/wear ring clearance is fine...now what?
Anybody want to buy a used Sportster LE with LOTS AND LOTS AND LOTS of new parts? Only thing is, it won't go over 5 mph...
Tim

 

[robin savell lloyd]

Did you have a good seal between pump and ride shoe?

 

[tawood]

Seal

I believe so...didn't look like that much to it.

 

[robin savell lloyd]

Did you buy a foam seal that goes between pump and shoe or what did you do to seal it? How good is your threw hull seal could it be sucking air there? did you make sure that the coragated hose is pushing against the ceramic seal? :cheers:

 

[tawood]

Must be model differences

But my boat doesn't have any of that....my pto shaft comes through the hull as just a sealed shaft, then connects to the pump. There is no pump-to-hull seal, no nothing, just four stud mounts to mount the pump, without gaskets or silicone, etc. For example, I could take my jet pump off the boat, then put the boat in the water, and I wouldn't take on so much as a drop.
When I took the pump off I was expecting it to be hard because everyone said there would be silicone, or a foam gasket, but it came off easy because there wasn't anything (or any need for anything) other than the rubber ring.
Oh, and with nothing but the ring, it worked fine before the switch.

 

[tawood]

Ok, just looked at the parts diagram

Shows sealant between the rubber ring (called neoprene ring) and the boat. I'll put some there and try again tomorrow. Not sure how it worked without it before though.
Tim

 

[robin savell lloyd]

The pump seal is not to keep water from entering the boat. it is to keep pump from cavitating. look at your parts break down it will show a seal #69. I do not know the year of your boat this one is a 2000. http://216.37.204.203/Seadoo_OEM/Seadoo_JB.asp?Type=13&A=46&B=13 :cheers:

 

[robin savell lloyd]

Go and buy it. it is a cheap gasket that looks like foam rubber and there is nothing beter in my opinion. :cheers:

 

[seadoosnipe]

Carbon ring....

Your boat has the carbon ring and carrier seal. This is designed to keep water from the hull, but if it's loose or worn, it can suck air into the impeller, low suction side, and cavitate badly.

Look at the rubber expansion spool on the shaft, where it attaches to the hull. This is stationary. Now, grab that spool and pull it back toward the back of the boat. If it's in the water, it will rush in through that spool until you let it go back up to the carrier ring. When you pull that spool back, look on the shaft, that metal piece you see is the carrier ring. It spins with the shaft, the carbon seal does not. If that boot has come loose, the clamps are loose, then you may be sucking air from the inside of your engine compartment. Look at those two pieces and make sure they mate up neatly and are "true" to each other.

Pump seal. You were lucky to pull your pump and not be faced with the silicone seal. I will mark that up as a first. I'd like to know what your measurement was or is now on the impeller to wearing ring, using a feeler gage.

 

[tawood]

The pump seal is not to keep water from entering the boat. it is to keep pump from cavitating. look at your parts break down it will show a seal #69. I do not know the year of your boat this one is a 2000. http://216.37.204.203/Seadoo_OEM/Seadoo_JB.asp?Type=13&A=46&B=13 :cheers:

Thats the neoprene ring I'm talking about, #69....got it, but I didn't put sealant on it because it had none before. I'll seal it up tonight and try again tomorrow.

 

[robin savell lloyd]

Your boat is different than mine I do see now where you are required to use a sealent. the brand that seadoo wants $50.00 for is called the right stuff. you can buy it at advanced discount auto parts. it comes in a chese wiz can. it is like $13.00. I would buy it and use it allso. along with a new neoprene seal. good luck Robin :cheers:

 

[seadoosnipe]

pump seal....

That too can cause it to cavitate. But, for me, when I seal mine, I use 100% sealacone gasket maker. Normally, RTV "blue glue"........works for me.

 

[robin savell lloyd]

The only thing I used was the neoprene seal as that is all it called for, I did use the right stuff in other places and I am willing to bet the right stuff would work all by it self, but as strong as it is I would think I might have a problem removeing pump in the future. :cheers: