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  1. #1

    What would y'all do?

    Hey gang, I have a 99 sltx. Last summer I did the ignition update and it ran fine. My question is I lost about 5 mph I get around 50. I check compression and get 120-mag, 117-center, 90-pto. Is it possible I slightly seized the pto piston(I did remove the oil pump and lines during the upgrade). Would y'all leave it have fun riding or fix only the low piston, or complete top end.


  2. #2
    Miglater's Avatar
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    I'd take the covers and heads off all 3 cylinders to examine each one, pto jug needs removed, need to check for metal debris in the crank case. Post up some pics of the cylinders etc....

    Does the ski still have the original grey fuel lines?

    When doing the oil injection delete, did u cap off the nipples where the oil line connected to the carbs? Was there any jetting changes made?

  3. #3
    I did not delete the oil injection, I just removed it with the mag cover when I did the ignition update. I did change all the fuel lines at the same time.

  4. #4
    Miglater's Avatar
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    I see, in that case..

    I'd take the covers and heads off all 3 cylinders to examine each one, pto jug needs removed, need to check for metal debris in the crank case. Post up some pics of the cylinders etc....


  5. #5
    Rasta Mon Condoms We Be Jammin!!!!! TxVirageTx's Avatar
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    might have a clogged screen on the pto carb.check there first.try to find what would have caused a lean out on the cylinder,then see about fixing it

  6. #6
    john zigler's Avatar
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    DO a leak down test on the motor BEFORE dis-assembly. This will tell you if you have any air leaks causing a lean condition.

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by john zigler View Post
    Do a leak down test on the motor BEFORE dis-assembly. This will tell you if you have any air leaks causing a lean condition.
    Good advice!

    Also remember to remove the PTO coupler from the rear of the engine before you loosen the engine mounts or remove the engine from the hull and before you remove the PTO cylinder head. Use the 'rope trick' to hold the crankshaft in position while you unscrew the drive shaft coupler.

    If it is later determined that the crankshaft needs to be rebuilt, it can be a bear to remove the drive shaft coupler with the engine out of the hull and especially difficult when the crank is already out of the engine.

  8. #8
    Thanks that's a good idea to do the leak down test, but I hate to tear into a ski that's run ok I just lost some mph. I think my lean seize (if I had one) came from me removing the oil injection and not bleeding it when I reinstalled it.

  9. #9
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    If it lost MPH its not running ok. You risk catastrophic engine failure if its down on compression like that any you continue running it. First do a leak down test. It involves removing the exhaust pipe and carbs and blocking the openings. That will show if a lean condition was caused by an air leak. Next, pull the cylinder head on the low cylinder and have a look. HEre are some pics of my leak test setup. I made rubber gaskets to use under the aluminum plates.

    Click image for larger version. 

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  10. #10
    Rasta Mon Condoms We Be Jammin!!!!! TxVirageTx's Avatar
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    could have been a leaking rear seal as well.

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