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  1. #1

    Red face 99 Yamaha GP800 HELP !!!

    i have a 99 yamaha gp800 that has been causing me some trouble i tried fixing it last summer but i never found out what the problem was. i thought i had to replace the battery since it died on me while i was in the lake, but even after getting a brand new battery its still doing the same..
    It runs fine for a few minutes but then it seems like it drains the battery or something and it will not go anymore ... you can jump start it but it wont have enough power to move just to start it.... this only happen while its on the water ; when i have it hooked up it will be just fine .... voltage while running fluctuates from 12.5-13 , compression is 100 and 125psi ... and i also got the rectifier replaced thinking it would make a difference... Any advice will be really appreciated... thanks a lot

  2. #2
    cfgp927's Avatar
    Join Date
    Dec 2005
    Warsaw, Missouri
    How did you check your compression? engine cold, throttle openeded fully, cranked over with a fully charged battery. Your compression numbers are low. Stock you should be at 125-135 depending on altitude you're located at. Once the engine gets up to operating temps, it's going to be very difficult to keep it running with the cylinders so far out of balance.....not to say it won't run, just won't run well. I think you need to investigate your fuel system as well, dirty carbs and plugged internal filters will cut off fuel needed to maintain anything above idle speed. Just a few thoughts

  3. #3
    i checked the compression right after i started it while it was being flushed and yeah the battery is brand new but it might of got drained last time it died on me at the lake .........someone also mentioned that it could be dirty carbs but recommened to drain the fuel and put new fuel in it and add some seafoam ..... i just purchased some but i need to investigate on how to drain the old fuel and also how much of that seafoam im suppose to mix with how much gas ..... thanks ....

  4. #4
    i put new gas an added seafoam as i was recommended i will have it running hookep up for 20 mins so that it does what its suppose to ... and then im going to take it to the lake to see how it works ... ill keep you guys updated....

  5. #5
    so we took it to he lake yesterday and rode the jeski for around 25 mins and it was just fine ...... today my brother took it back to the lake thinking it was going to be fine but after riding it for 30+ , it died on him , he said it seemed like it was going to start right back up but then not even a click anymore ( battery was out).... i dont know what else to look for ..... thanks in advanced for any advice that might help solve this issue .....

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