1994 sea rayder sort jet 90 impeller question.

Staniel

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Aug 16, 2015
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i have a 1994 sea rayder jet boat with the 90 hp sport jet motor and am having trouble getting up to speed. I max out at about 10-15 mph. It's a new boat to me. I am an experienced machinist but not very knowledgeable yet about jet boats. I saw the impeller was looking pretty rough and the housing was badly worn so I machined a ring to put in the housing which I bored out to fit it. I may have made a big mistake though. The machining all went very well and it fit great with 10-15 thousandths inch gap which should have actually made it better than factory from what I have read. The thing I did that maybe I shouldn't is that I turned the outside of the impeller blades to clean up the ends and maintain that tolerance for the entire length of the blades where they meet the ring diameter. Was this a big no-no? Are factory impeller blades the same distance from the ring at all points of contact?
Is it possible that I threaded the impeller on backwards when re installing it? I'm lost and really want to get this thing running good before summers gone. The boat is mint condition and motor runs great I'm just not sure what it really needs. Any help would be greatly appreciated. Thank you,.....Stan
 

GA_Boater

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:bump:

Can anyone lend Staniel a hand here? Thanks.
 

JimS123

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If it was threaded backwards the boat would go backwards. Did you replace the original wear ring with the new one, or put the new one on top of the old one? is the engine reaching full rpm? Is the boat waterlogged?
 

Staniel

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Aug 16, 2015
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Thanks for responding jim, I bored out the original wear ring and put an aluminum ring back in it that is bored out to match the diameter of the impeller plus .01 clearance on both sides. They don't have a replaceable wear ring like most models, you have to buy the entire housing for about 450$ if you can find one. If the boat is water logged where would the water be? There is no visible water around the sub pump by the motor. I think the motor is reaching full rpm, I have tried manually with my hand giving it more rpm at the carb and it doesn't increase any more than using the lever.
 

JimS123

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Sounds like you did a well thought out job. Waterlogged hulls are usually full of water on the inside guts of the hull. If you could weigh it on a truck scale you could compare it to specs. You can buy an inexpensive "tiny tach" to verify rpm. Really no boat should be without a tach.

Are you sure its firing on all cylinders? That may sound intuitive, but I have a very strong old Evinrude that lost a coil once and I really couldn't tell until I went wot and had no speed.
 
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