1998 Sportster 150 (single engine) Cavitation Issue

[yetisoldier]

I'm pretty new to jet boats and recently purchased a 1998 Sportster (single engine). The boat is in great overall shape, but I can't get it to go properly! With just me in the boat I can slowly get it up to about 33 mph, but under hard acceleration or with more weight it just cavitates violently (10mph max)! I've had the wear ring replaced, and even tore the pump apart again and put it back together with liberal amounts of sealant to see if that helped. No dice. After looking around I think I may need to remove and re-seal the pump shoe/ride plate. I can't find any good pictures for this model anywhere. I understand there are 6 bolts and sealant that hold it on. My question is do I need to remove the pump before attempting this, or can I do it with everything in place? I want to minimize the amount of time spent on this and ensure I have the proper parts on hand. Any advice, pics, or instructions are appreciated!

 

[whitewheels]

Haven't done it myself but lookin at the manual it seams to be a pretty amount of work with the rideshoe. Someone else can comment,but I don't think the rideshoe usualy cause any problem. Have you checked the carbon seal and pre-load of it?

 

[yetisoldier]

I am going off of this comment found elsewhere. I don't think the carbon seal has been replaced or checked. I'll have to look into that.

Pump Shoe - The pump shoe is the actual metal part (bolted to the hull) that the pump body seals up against. In the case of the 14.5's, the shoe and the ride plate are made as one piece. It is "fundamental" that this shoe/ride plate is perfectly sealed to the hull with a high-grade silicone sealer. Herein lies a lot of the cavitation problems experienced by many 14.5 owners. Many of these shoes came from the factory with breeches in the silicone that sealed them to the hull. On these units, no kind of custom prop, etc, can eliminate the cavitation. The pump shoe/ride plate "must" be removed and resealed using "Permitex 66c Industrial Clear Silicone" (available in auto parts stores). Removal of the pump shoe is difficult (usually done with a hydraulic jack between the plate and the rear swim step). Once off, all surfaces must be completely cleaned of the old sealer. It is impossible to over emphasize the absolute importance of have this area attended to. We recommend This procedure for "every" single motor 14.5.

 

[ottawaguy]

Hey. I just bought a Speedster that was taking in water. I just used silicone on all outlets including the exhaust and left the jet pumps alone (hoping it's not them). I also installed an automatic bilge pump. So far things are much better just using silicone. Good luck!

 

[whitewheels]

I am going off of this comment found elsewhere. I don't think the carbon seal has been replaced or checked. I'll have to look into that.

Pump Shoe - The pump shoe is the actual metal part (bolted to the hull) that the pump body seals up against. In the case of the 14.5's, the shoe and the ride plate are made as one piece. It is "fundamental" that this shoe/ride plate is perfectly sealed to the hull with a high-grade silicone sealer. Herein lies a lot of the cavitation problems experienced by many 14.5 owners. Many of these shoes came from the factory with breeches in the silicone that sealed them to the hull. On these units, no kind of custom prop, etc, can eliminate the cavitation. The pump shoe/ride plate "must" be removed and resealed using "Permitex 66c Industrial Clear Silicone" (available in auto parts stores). Removal of the pump shoe is difficult (usually done with a hydraulic jack between the plate and the rear swim step). Once off, all surfaces must be completely cleaned of the old sealer. It is impossible to over emphasize the absolute importance of have this area attended to. We recommend This procedure for "every" single motor 14.5.

Yes your probably right,I have the big pump and thats a different story

 

[Dadasaurus]

My Speedster cavitated badly when we first purchased it. I changed the carbon seals and it now runs terrific. Just a thought.