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Thread: What do you think happened to this Sport Jet?

  1. #1
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    Default What do you think happened to this Sport Jet?

    My Brother has a 200 SportJet in his Alumaweld Intruder. He was out one fine day on the lake when the engine over revved (and kicked in the rev limiter) and then no jet. Engine still runs fine, no loud bang, no smoke, no grinding noises. No jet when he was out on the water, he kickered back in. You can spin the impeller shaft freely now when you reach up through the intake. So, what happened? Neither of us know much about the guts from a SportJet, but we are fixin to find out over Christmas break. Now, if his boat had a 350 and a Hamilton, we would not have this problem, and if we did, I would know why.

    We would like to do this in the comfort of his shop down in OR over a few days if possible so we can use it this year when I am down there to fish for Sturgeon, so this is IMPORTANT.

  2. #2
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    Get ahold of gravelpumper or jtm, Mel Be you best bet.
    When the motor is off you can free spin the impeller is normal.
    Do I give my friends advice? Jesus, no. They wouldn't take advice from me. Nobody should take advice from me. I haven't got a clue about anything..

  3. #3
    Premium Member bmunsell's Avatar
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    Just thinking, but that don't sound right. How could the impeller spin free anytime, motor on or off. Aren't jets on a shaft that is hard bolted to the motor? I know my Kodiak 3 stage is bolted to the motor. The only way the impeller would spin free is if the couple between the engine and the jet was broken, the main shaft in the jet was broken or the keys in the impellers were sheared off.

  4. #4
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    Quote Originally Posted by bmunsell View Post
    Just thinking, but that don't sound right. How could the impeller spin free anytime, motor on or off. Aren't jets on a shaft that is hard bolted to the motor? I know my Kodiak 3 stage is bolted to the motor. The only way the impeller would spin free is if the couple between the engine and the jet was broken, the main shaft in the jet was broken or the keys in the impellers were sheared off.
    Ya, it is weird. The shaft spins with the impeller like it should, it just does not spin when the motor tell it too. It is not an impeller problem. Like I said, if it was a Hamilton, I would get it.

  5. #5

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    Quote Originally Posted by Daved View Post
    Ya, it is weird. The shaft spins with the impeller like it should, it just does not spin when the motor tell it too. It is not an impeller problem. Like I said, if it was a Hamilton, I would get it.
    Daved, sounds like you could have broken a shaft or gear in the gear box of the intake housing. The SPJ uses a 1:1.25 gear reduction so it sounds like something failed in there. Pull the engine and check the out put shaft, if it's ok then you have a failure in the gear housing.
    You can get a parts breakdown on our new parts website http://www.fnmmercurymarineparts.com. If you order online you'll get 10% off and free shipping on orders over $100.

    I've attached a screen shot of what I'm referring to. Hope this helps.

    Mel
    Attached Images Attached Images

  6. #6

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    Probably sheared the key between the shaft and impeller

  7. #7

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    Quote Originally Posted by LastSplash View Post
    Probably sheared the key between the shaft and impeller
    The SPJ shaft and impeller are splined not keyed and I've never heard of this failing. I believe he said the shaft is turning when you spin the impeller. The shaft shouldn't spin unless the engine does.

  8. #8
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    Gears failed, usually the impellor shaft seal fails, water replaces gear oil, bearings and gears fail quickly because water makes poor gearlube. The pinion and side gear take special tools to set backlash ect. Nothing to tricky, someone with mechanical skills, a dial indicator and a set of shims should be able to handle it.. like hg said, the gears are splined not keyed, the input shaft for the jet is splined on the crank end and engages the crank, the pinion gear is on the other end, never seen an input shaft or impeller shaft break on a sportjet but have seen bearing failures from seal failure usually from fishing line or pushed out from water freezing behind the first seal .

  9. #9

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    Quote Originally Posted by akgravelpumper View Post
    Gears failed, usually the impellor shaft seal fails, water replaces gear oil, bearings and gears fail quickly because water makes poor gearlube. The pinion and side gear take special tools to set backlash ect. Nothing to tricky, someone with mechanical skills, a dial indicator and a set of shims should be able to handle it.. like hg said, the gears are splined not keyed, the input shaft for the jet is splined on the crank end and engages the crank, the pinion gear is on the other end, never seen an input shaft or impeller shaft break on a sportjet but have seen bearing failures from seal failure usually from fishing line or pushed out from water freezing behind the first seal .

    Thanks AK and hallig....learning a lot from this thread!!...200 sj is going in our new boat!!.....( note to self)"splined not keyed!!"..larry

    29' Wooldridge Pilot House, Twin 200 Hp Etecs! "...Pez Gordo..."
    18' Wooldridge Sport with 200 hp sport jet. "...Little Pez..."

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