1995 Speedster Port Eng. Cavitates when RPM go over 5500

[Tysonk]

Hello,

I recently tried to repair cavitation in my Port side engine. Prior to repair, When excellerating upto 5500 rpm the engine and pump run just as expected. As soon as the rpms go over 5500 the pump cavitates and the rpm jump to 7k and bounce off the rev limiter.

Now, having a little experience with these boats, I ordered a new OEM wear ring and a drive line repair kit. (http://www.sbtontheweb.com/Merchant...0-101&Category_Code=1995sdsp&Product_Count=16). I did a full pump rebuild, installed the new wear ring, and the drive line repair kit. I fully expected this to fix the problem.

However it did not. After water testing the motor it was apparent that the problem was still there. Same problem, runs fine to 5500rpm then jumps to 7k and bounces off the rev limiter.

Anyone have any ideas? I thought the parts I installed would correct any cavitation whether is was the wear ring or sucking air through the ingine compartment.

Is this how all 1995 speedsters run? seems unlikely.

Any ideas?
Tyson

 

[kustomkarl]

Check the jet pump assy. for air leaks. Use silicone if needed to seal it up. Check the carbon ring as well. Its pulling in air allow it to cavitate.

Karl

 

[Tysonk]

Thanks for the reply Karl,

When I rebuilt the pump I siliconed every joint/connection thoroughly and rebuilding the pump had no effect on the symptoms.

The 95 does not have a carbon seal I believe. It has the driveline seal assembly with double lip rubber seal on each side. Replacing it made no difference.

 

[Tysonk]

Another thing I would like to add is that it will cavitate if RPMs are over 5500 whether the boat is at a stand still or full speed. If I pull back on the throttle of the port engine when it is cavitating it will drop back down to 5500 and stop cavitating until more throttle is givin.

 

[phough5757]

How about?

In a boat that old, could the ride shoe or sole plate be coming loose?
Also when You replaced the drive line kit, How was the fitting on the hull?
Did it seem loose, cracked or thin? I hope the rubber tube was good.

 

[Tysonk]

I will have to check the ride shoe but I dont think that is the problem.

I used ultra black on where the rubber tube joins the hull, and tightened the gear clamps down well. The tube looked in good condition. I should take another look though, thanks for the ideas.

Could a problem with the impeller cause this? If the prop was not balanced at high speeds would this cause these symptoms?

Would there be a problem putting an aftermarket impeller on one motor and an OEM on the other motor? This year of boat does not have the same impellers on both pumps to make up for the single water intake.

Thanks
Tyson

 

[kustomkarl]

Don't forget to add your seadoo model and year to your avatar for future problems and questions.

Karl