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  1. #1

    Angry New engine, mag cylinder smoked again wtf why

    I am ready to beat this fukn ski up and toss it in the dumpster. This was a hour of IDLE TIME ON IT. Took it out again after thinking I fixed a issue with the battery. Pulled plugs and the fukn mag cylinder is toast again.. ZERO COMPRESSION. I put new pistons rings and all seals in this thing. No short cuts.. What the hell could be doing this.. I am not into this bucket way more then it is worth. The carbs and all were back to fact settings.. Oil was mixed with the gas, in the injection tank.. Smoked plenty.. Im lost..


  2. #2
    800AMSOIL4U's Avatar
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    Did you pressure test the engine after the rebuild? And rebuild the carbs?

  3. #3
    Carbs were gone through and set back to factory specs beside the low idle screw. Oil lines were checked and blew through with air. I can crank the engine with out that cylinder on it and smell the gas being pulled into it now.. I thought it was a battery issue and put a new battery in it. Toolkit out and after a few seconds of mid throttle it died in the water almaot like it went to safe mode or something. . The cylinder has what looked to be marks in it that is not into the wall but built up outside . And again I had oil in the gas as well. It makes no sense.

  4. #4
    I like pipes. I love boost Mr. GP1800's Avatar
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    Pics? Did you check and verify your timing? What fuel were you running? Did you leak test the motor before installing it? The flywheel housing where it mates to the motor is a critical sealing point. What did you use for sealant on it? All little details, but very important ones.

    Leak testing a motor is a critical step in my mind before installing it. I do it to every motor I build.

    Its all in the details.

  5. #5
    Connecticut CrazyA's Avatar
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    Yup. Sounds like an air leak somewhere.

  6. #6
    The entire engine was sealed up using Honda bond. I specifically made sure that the stater housing was sealed well. The timing remain the same as stock everything went back together as a stock set up would. I did not do a leak down test however. I have never in my life had this much issue with a 2 stroke engine, have built many many 2 strokes..
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  7. #7
    I also find it strange that the previous owner had replaced only the front 2 Pistons and never the rear one. I wonder if the block is messed up some how but a leak down test would have solved that. This is probably going to turn into a parts ski.

  8. #8
    800AMSOIL4U's Avatar
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    Quote Originally Posted by Fenderjack View Post
    The entire engine was sealed up using Honda bond. I specifically made sure that the stater housing was sealed well. The timing remain the same as stock everything went back together as a stock set up would. I did not do a leak down test however. I have never in my life had this much issue with a 2 stroke engine, have built many many 2 strokes..
    It is not a leak down test you need to do. You need to seal off the intake and exhaust system and pressurize the system to make sure there are no air leaks.

  9. #9
    RLACEMAN's Avatar
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    Did you have the engine out & replace crank seals? If not I am guessing the mag side crank seal is bad.

  10. #10
    yes all seals were replaced with OEM polaris seals. The only thing I can think of is that the oil system some how malfunctioned. I have found a small amount of 2 stroke oil on the front carb... I am not pulling this engine back out again will go through the carbs again, run pre mix only.. Does these skis have limp or safe mode that would cause the ski to cut the engine ?? Rear cylinders show like new compression.

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