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  1. #1

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    97 SLT 780 piston damage

    Any thoughts on the likely culprit? Center cylinder, PTO & MAG are fine.
    Carb is clean, jets are good, needle seat replaced a few years ago. (we only get a couple months run time here in Canada). Gaskets look good, cooling system seems ok. Ordered another piston but likely burn it also if I dont figure out the cause.

    Thanks
    Al
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  2. #2
    RLACEMAN's Avatar
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    Definately not enough fuel getting to this cylinder, most likely a carburetor issue from storage. what type of fuel are you using? The 97 models had the high speed screws turned out only 1/8 from seated, I would double check that & keep them at least 1/4 turn out with todays fuels, a little rich is better than lean.

  3. #3
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    Thats crazy lean. I would be checking for air leaks in the motor. Go through the carbs again looking for anything funky in the center carb like a plugged filter or a sticking needle and seat. It has to be an issue with the carb or an air leak or both.

  4. #4

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    This ski has the filter on the main fuel supply not in the carbs. I did richen up the HS adjuster but figure there must be more going on. Needle seat would be my starting point and I will do a pop off test.
    I have learned from experience crossing ones figures just leads to another tear down. (gets costly)

  5. #5
    BlueFishCrisis's Avatar
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    Quote Originally Posted by IndyAl View Post
    This ski has the filter on the main fuel supply not in the carbs. I did richen up the HS adjuster but figure there must be more going on. Needle seat would be my starting point and I will do a pop off test.
    I have learned from experience crossing ones figures just leads to another tear down. (gets costly)
    Each of the three Mikuni carbs has a small filter in it. These need to be checked. Remove the fuel inlet plate on the carb. It is a small black round filter directly under where the fuel enters the carbs. Post #3 http://www.greenhulk.net/forums/showthread.php?t=217669

  6. #6

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    This has the black carbs on it but now that you mention it likely has the same inlet filter. I will check it out as it would certainly cause a problem if getting clogged up.

    Thanks
    Al

  7. #7

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    ok I checked the filters in the carbs, all were spotless. pop off on needle is 18psi. intake gaskets on carbs, stuffer box (reeds), all look good, crank case has never been apart so I assume seal is good. Both PTO & Mag pistons look fine. Any other suggestions? I honed out cylinder and installed a new SBT piston. Should have her back on the water this week but dont want to burn new piston down.

    Thanks
    Al

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