95 Speedster cavitating

[gener8s]

Hi all,
I'm having yet another issue with my boat. My port engine/pump is cavitating pretty bad and I was in the prosess of pricing out a wear ring when someone suggested that I may be having an issue with my driveshaft seals. My question is, if my seals are bad causing my pump to suck air in, would I not be taking on water through those seals when sitting still or at the dock? Any suggestions or input would be greatly appreciated.

 

[gcha1727]

I would have to agree with you. But maybe its poss. the seals react a little different when the driveshaft is turning. I would look at the seals at the dock running and not running to compare. if the wear ring needs replacing then that could fix it but you may have multiple problems. check your impeller and wear ring to be within proper range. to my understanding cavitation is caused by both damaged parts in your jet pump or the pump sucking air.

 

[Dr Honda]

On the old style seal pack... you have 2 seals. Both face out. The rear seal holds water out, and the front seal holds air out of the pump. Rubber seals are designed to work in one direction, so if your front seal is burnt... then it can suck air, and the rear seal will still hold water out. Also... the vacuum is high, and the water pressure is low... so cavitation is experienced first.

If you think it's the drivshaft seal... give it a few good pumps of water-proof grease. When it's full, it will keep the air from passing though. But, as the grease washes away... the cavitation will come back. If you fill it with grease, your leak is somewhere else.