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  1. #1

    something stripped or cavitation on 97 gp1200

    I tried to post this last night, but can't find it. Maybe my phone didn't upload it, anyway sorry if this is a double post. Pulling onto the trailer the other day, gave it some throttle, and it moved up a little, then just revved, with no power, and some new vibration. Didn't really worry about it, thought it was out of the water or something. Anyway, I was having carb problems, so i adjusted low speed needles and went back. In the water it would idle fine, but when you give throttle, it would give a tiny bit of thrust, then just rev with that vibration. I know, i know, check the water intake for obstructions, but i didn't. I got on greenhulk and decided i had a stripped shaft Went home flushed it out with the hose, rolled it back in the garage. In the driveway i found a piece of boat trim about 10" long, and i said to myself," that's what stripped it". Now the ski is apart, main and intermediate shaft out, the splines look fine on drive shaft, intermediate splines look pretty good too. would that piece of trim cause that much cavitation, or do i need to check something else while i am in there? Can the coupler on the engine slip, or strip? Lastly what needs to be shimmed? there weren't any shims on intermediate housing, but there were on the motor mounts. Not sure which ones were on which mount( rookie mistake). I know there were 2 thick shims on the front left, does that mean 2 thick shims on back left? If so i know where the rest go.


  2. #2
    showmepro1200's Avatar
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    If you found a 10 inch piece of plastic trim in your pump (or it blew onto the driveway while flushing), then that's likely the cause of the cavitation. Anything, even as little as just a sliver of wood or something, can cause major cavitation in the pump.

    Re the shims - yeah you made a rookie mistake not keeping track of the shims on each corner (I always bag em and tag em LF, LR, etc.) Now you'll have to do some experimenting with them to reinstall. Its all about the orientation of the two coupler pieces between the PTO and the midshaft assembly. You should end up with about 1/8 inch between them when in place and you have to turn the assembly by hand to make sure its straight when rotating. Also, I found its very important to use a torque wrench (or a very accurate wrench ability) when mounting the midshaft assembly back on the midwall, it affects the orientation of the whole assembly greatly.

  3. #3
    Worked on it all day. Played with the shims and had it real close, went to lock it down and one of the motor mounts stripped. The top, threaded piece seperated from the rubber. Went and got a torque wrench, and plan to work on it tomorrow. I got the specs from the service manual... 0-1mm height difference, 2-4mm gap between. The top of the I-shaft coupler is a little above the tpo, within the 0-1mm range. With the top like that the bottom is the opposite, tpo less than a mm higher than the coupler. How perfect does this have to be? Do you just eyeball it and get it straight, or do i need to keep working on it? Kind of excited about the torque wrench, i'm gonna torque every bolt i see. 2 years ago i took it out for about 5 minutes, hit one little wake, and when i landed, it died. Pull off the seat, and the whole flywheel cover was seperated from the engine. $90/hr and a new magneto = $1200 and 2 months to get it back when it was too cold to ride. I will never pay anyone to work on it again(unless payment is beer). Oh, and Thank You for the help.

  4. #4
    Yamaha artisan Cutlass's Avatar
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    Quote Originally Posted by jimballs View Post
    How perfect does this have to be? Do you just eyeball it and get it straight, or do i need to keep working on it?
    The more perfect it is, the better. It puts less stress on the bearings and the rubber coupler. But you do have a little wiggle room for slightly imperfect alignment.

  5. #5
    showmepro1200's Avatar
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    Quote Originally Posted by Cutlass View Post
    Quote Originally Posted by jimballs View Post
    How perfect does this have to be? Do you just eyeball it and get it straight, or do i need to keep working on it?
    The more perfect it is, the better. It puts less stress on the bearings and the rubber coupler. But you do have a little wiggle room for slightly imperfect alignment.
    +1 on what Cutlass said - the rubber coupler is forgiving on offages but the closer you get it to perfect the faster your pwc will run - ok well not really (haha) but it will likely run more smoothly and trouble-free with regards to that area
    Last edited by showmepro1200; 07-05-2013 at 08:19 AM.

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  7. #6
    installed the monkey grip motor mounts, got it all lined up and put back together. ran it today and was hitting 65 constantly. Thanks for the help guys.

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