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  1. #1

    Join Date
    Sep 2012

    '90 550sx running weird

    I have a '90 550sx with a coffman halfpipe and a water box, everything else stock, that runs great but only if I don't let it idle for very long. If it idles for more than 30 seconds it won't rev up no matter what. When it gets like that I have to shut it off for a minute or two and then fire it up and ride away. Once it gets going it runs perfectly normal. I have been stumped by this for a while and have just put up with it but have now decided that it is time to sort out the issue. Compression in both cylinders is in the 120-125 range and it has a new head gasket, spark plugs, and a fresh carb rebuild. Any help would be greatly appreciated

  2. #2
    Sounds like your pilot fuel setting is set too rich and engine is getting flooded.
    You may want to make it little leaner by scrweing in the pilot screw like 1/4 turn at a time.

  3. #3

    Join Date
    Sep 2012
    Thank you, I had ruled out carb settings because one of the times I took it out before I realized that if I let it sit it would run I tried playing with the carb but nothing worked. Now that I think about it though, all these issues started after I messed with the settings a few months ago. I will try that and hopefully it will work.

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