Still having Cavitation issues!!

[paulym]

1998 Sea Doo Sportster (single engine)

I have just repaced the wear ring, neoprene seal, and carbon ring and boot. i took the boat out and it felt stronger when coming out of the water than before but still had cavitation pretty bad. The 3rd or 4th time I could not even plane out, i did have the carbon ring in the 2nd groove and moved it to the 3rd groove when i just got home. Will that fix the problem?

I was also looking at the engine in the water while it was running and noticed it vibrated alot, i had the top end rebuilt last season and have good compression. I was wondering how much vibration should an engine have if any? When i push on it i get about 2 inches of movement.

 

[kicker]

2 inches is to much movement, you probably have a loose motor mount which is possibly not letting your carbon ring seal properly

 

[robomatic12]

2inches is probably a broken motor mount!

 

[Dr Honda]

yep... what they said.

If the engine is moving... the seal can't do it's job. If the mounts are good... and the bolts are tight... the engine should only flex a small amount.

 

[paulym]

SO there should be little to no movement form the engine at idle? It looks like a Harley engine sitting at a red light when i start it up. The engine does run smooth and strong. I will check all the bolts today and see if that fixes the problem.

 

[kicker]

no movement at idle. A slight vibration of things but definitely not a movement.

 

[paulym]

Yesterday i went in an looked closely and the engine was moving on the mounting plate. So i unbolted it from the engine mounts and lifted the engine and tightend all the nuts on the bottom of the mounting plates at least 4 to 5 turns. When i restarted the boat the engine was very smooth and put it in the water and the cavitation was gone.

The part that is so frustrating was i had the boat at an AUTHORIZED SEVRICE dealer and they replaced the stator and i told them about the cavitation and they said replace the wear ring which had just been done!! Not sure how they could see that engine running when water testing and not see the problem?

Thanks to all for your help!

 

[kicker]

If you dont mind turning a wrench here and there, you will not have to visit the stealership to often. Research the forum and ask the questions that you need answers to. There is a good chance you bought and installed that wear ring for nothing.

That being said, if you did not put loctite on the bolts before re-torquing them, you will want to monitor them closely to make sure they dont loosen up again

When the engine gets moved around like that it really should get re-aligned with the pump again to be sure there is no binding. Was there any spacers of any kind on the engine mounts, did they go back exactly in the same spot?
Make sure to keep the PTO lubed.

 

[Coastiejoe]

It is a shame that an "Authorized Service Center" misses things so easily.

Glad your solution wasn't a nightmare to solve...

 

[paulym]

I left the mounts bolted to the boat and just removed the plate, the bolts went right back where they came from. Is there any way i can check alignment of the engine to make sure it is correct?

 

[kicker]

Unfortunetly you will need a special tool which is $150 to buy or 75 to rent from SBT. Basically a plate get mounted where your jetpump is and you slide a long rod through the plate and into your pto, if the rod does not slide in without hitting the pto you would have to shim the motor until it goes in smooth.

I am not that familiar with the mounting of your motor, so wait for one of the other guys chime in to see if they think it should be realigned.