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#2 piston has a hole...88 Yamaha 90

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  • #2 piston has a hole...88 Yamaha 90

    Bought a used outboard off e-bay, an as is special..

    a 90 ETLG. #2 piston had a hole in it, just wondering how big of a deal this is to repair... Anyone from here from around southern ontario do it?


  • #2
    For what it's worth..from my limited experience with 2 cycle jet skis...The hole was caused by a lean condition in that cylinder.

    When a cylinder is lean, it runs HOT and then burns a hole in the piston..

    So it means that your carb is jetted too small(by someone)[or has gunk in the jets-making it smaller---] and/or it is sucking air some where(around crank seals etc).

    To verify the source of the leak, the case has to be (blocked off) and pressure checked.

    Just replacing the piston will not solve the problem.

    I'd verify all correct carb jets first.

    Post what you do and find.

    Cheers !!


    • #3
      Should I clean out #2, put the head on and do a compression check? Is that what your suggesting?

      I'm also wondering..if I crank over the engine (say by means of impact gun on the flywheel nut, or the safer way of jumping the starter...) is this type of motor / ignition system suppose to spark?



      • #4
        If #2 has a hole in it---compression check will do nothing. Bottom line you are running lean(Hot) and may possible have 1 or many air leaks. Compression checking will not identify air leaks.

        Check on this board for the correct part numbers for jets (for each carb-as each my be different)--jets are cheap.

        Clean the carbs--.-and /or-purchase carb kits with the proper gaskets.

        The replacement piston needs to be matched to the respective cylinder bore(machine shop job)all cylinders should be the same (oversize)size.

        The possibility of an air leak is High....which means new seals. has Clymer Manuals for $29.00...good maintenance books !!!!!

        ....I don't know about the other stuff you asked.

        Hope this helps....