Ride plate seal

[cshermach]

I have a 90hp sport jet and have the issue of getting on plane efficiently when there is more than one person in the boat ('95 jazz). I just crawled under and notice the seal on the drive plate is dry rotted in the corners. The boat runs great and goes pretty well once on plane just takes forever when there is more than 300 lbs. on board. Is this rotted seal contributing to the lack of bottom end power? Thanks.

 

[calledinsick]

Re: Ride plate seal

From my experience you will loose top end or never get on plane if the ride plate is bent or not sealed. Generally that would result in cavitation (sounds like it's reving in nuetral). The smaller fiberglass boats seem to benefit from Trim Tabs.

Also, try distributing your weight differently...move a person forward in the boat to take off and get on plane.

You might look at this thread:
http://forums.iboats.com/showthread.php?t=421298&pagenumber=

 

[cshermach]

Re: Ride plate seal

Thank you for responding. I do have trim tabs and agree moving a passenger does help get on plane. Without moving the passenger forward it will take forever to plane off or never. I am thinking maybe my performance expectations are a little beyond reasonable? After additional reading I think I will pull the jet apart and check the gap between the impeller and wear ring. I may just replace that ride plate seal for the $50 while I am at it. I've seen pictures where people have loaded silicone sealant around the ride plate seal. Although it looks terrible would this be a good way to test that seal? Any thoughts would be appreciated. Thanks

 

[Fireman431]

Re: Ride plate seal

It sounds to me like your needing to replace the wear ring. Loss of power and thrust...

 

[calledinsick]

Re: Ride plate seal

Start off with the easy first.

GPS your top speed. I'd like to know you're getting full thrust all the way thru your throttle range. I think 34-38mph (by GPS) should be about top speed.

Verify your reverse gate is clearing your jet nozzle in forward. It should also not have much play in it. It should clear the jet nozzle in forward and about 1/2 way cover it in nuetral. Also look in through the end of the nozzle (put in forward to move the gate out of the way) and make sure there aren't any obstructions (rocks, leafs, etc.) on the aft side of the impeller.

You should also look up thru the intake grate at the leading edge of the impeller for nicks/gouges.

If those all pass then move deeper and check the clearance on the wear ring.

If you're not cavitating I don't think I'd mess with the seal unless you take the ride plate off.

If it ain't broke, don't fix it!