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  1. #1

    1998 GP1200 not reaching full RPMs

    Good compression, checked it.
    Good spark, checked all three plugs and wires, and have new boots.
    No reason to suspect fouled fuel, was treated with Stabil and is pre-mix 40:1


    I bought the ski used 3 years ago and aside from handling issues which I fixed with trim tabs; all has been great.


    First, I don't think these are stock carbs; can someone please verify?
    It has primer kit installed only plumbed to first carb, and I see no provisions for choke plates.
    It has Tau Ceti individual flame arrestors too.






    Regardless, they appear to be all working fine. They are synced, and all flowing evenly.






    The ski ran fine all last year. For the hell of it, I decided to install a TDR waterbox at the end of last season. It ran fine on the hose/trailer, but I never water tested it.


    This year, I took it out for the first time after installing new NGK plugs. I had an issue with not reaching RPMs, and found out I had a spark plug tip come off in the spark plug boot. I destroyed the spark plug boot trying to get it out, so I replaced all 3 spark plug boots with new ones from NGK.


    It was still not reaching full RPMs. As soon as I squeeze the throttle to open the carbs just past 1/4 inch it sounds like it's banging on an electronic rev limiter.


    Tonight, I put the stock waterbox back in and tried to run it on the trailer/hose again. It still has the same issue where it sounds like it's banging on an electronic rev limiter.


    I also now have about 1/2" deep of oil in the bottom of the hull.





    I have a service manual. If anyone has any pointers on what to check first/primary; I am all ears and very thankful.


    Brian


  2. #2
    Yamaha artisan Cutlass's Avatar
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    Quote Originally Posted by Sydwayz View Post
    First, I don't think these are stock carbs; can someone please verify?
    It has primer kit installed only plumbed to first carb, and I see no provisions for choke plates.
    It has Tau Ceti individual flame arrestors too.
    You are correct. They are not the stock carbs. They are Mikuni SBN carbs that have been modded by some company (Novi, BlackJack, Buckshot, etc) but I don't know what brand they are.

    If you are experiencing a 'rev limiter' feeling, check the ignition system out. Run all the tests in the ignition system section of the manual. Maybe CDI, Stator, or temp sensor could be you issue.

  3. #3
    It was the stator. There was way too much buildup of grease and gunk in there, and the main culprit was two pieces of electrical tape that had come loose from the wiring harness and were dancing around inside the stator housing.

  4. #4
    Well, ran great for about 30 minutes today today, the rest of the time it was acting up again. I am now looking for someone to test and diagnose the issue somewhere around Richmond, VA if anyone has any good shops or mechanics to recommend.

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