Cavitation problem

[air.boss1]

I have a 1996 speedster, I just got it. When I go more than 1/2 throttle at start I get cavitation, it is worse with 2 persons in boat. I checked wear rings and have .020 clearance. I ordered new rings....any other suggestions? I just installed new driveshaft on right engine with new o ring. I did not use any sealant on pump when I replaced it, is it required? (none on it when it came off)

 

[LouDoo]

You need to use a neoprene seal (washer) between the pump and the ride plate, you only need sealant where the pump fitting penetrate the hull. If you didn't use the neoprene washer that's your problem.

Lou

 

[air.boss1]

Lou,
the speedster has no ride plate under the pump the ride plate is in the center between the engines.(am I wrong?)

 

[LouDoo]

I wasn't aware of that, so the pumps just mount directly to the hull, then you especially need the neoprene seal, actually it's kinda optional if your pump is mounted to a ride plate.

Lou

 

[Dr Honda]

There is a ride plate and mount at each pump. It's what seals the water inlet, and the part the pump bolts to.


But your cavitation is a bad carbon seal. With the "Suction" is low... it's OK. When it's high, you have cavitation. SO... you are simply sucking the seal open. Remove the covers over the PTO, and take a look. The 96 will have the O-ring support on the stainless ring. There is a good chance that they have rotted, and fallen out.

 

[air.boss1]

I already replaced the "oring and carbon seal" The carbon seal seams "too loose" is it supposed to fit tight on the driveshaft? the hole seams like it is too big. Did I get the wrong seal? Is there supposed to be a gasket between the rideplate and the pump? Or should I use a sealant?

 

[Sportster-2001-951C-Stock]

Here's a couple of cheeky-monkey drawrings that might help:
http://fiche.seadoowarehouse.com/se...=seadoojb&a=187&b=14&c=0&d=-PROPULSION-SYSTEM

This one shows item #10, which acts as a spring to tension item #14 against item #8 to keep water out of boat and air from being sucked from bilge into pump while under way, item #9 keeps item #8 correctly positioned on the drive shaft and item #14 makes the seal to item #8 as the item #8 rotates with the drive shaft:

http://fiche.seadoowarehouse.com/se...asp?Type=18&make=seadoojb&a=187&b=13&Action=O

If you don't have item #12 installed in both ends of the drive shaft then the tension from the item #10 and the position of item #8 may allow an air leak?

Are both screws experiencing identical symptoms? They might if they were assembled the same way and a slight mistake was made during the process?

Oh, and over time item #10 can become hard and compressed because it's just a rubber spring, so it may need to be replaced if it's done for.

 

[air.boss1]

I just did some more looking.....O ring does not stay in place, can I replace it with a "c"clip?