Discussion in 'Troubleshooting & Diagnosis' started by RRMetallic77, Nov 29, 2002.

  1. RRMetallic77

    RRMetallic77 New Member

    Nov 29, 2002
    How do I tune a carburetor? I mean, is there a certain way to adjust my air and fuel mixtures to get my car running right? Oh, and I have a problem with my carb spitting up gas once in awhile after I turn off my car, and I have no idea why. Running too rich, maybe? I don't know... This has been making me very angry, and I've been messing with my carb for a while now trying to get my car to run good. Maybe the carb just needs a rebuild. Can someone help?

    [This message has been edited by RRMetallic77 (edited November 29, 2002).]
  2. 79er

    79er Member

    Nov 3, 2002
    LA, California
    One simple test on a carb is if you can screw the air fuel mixture screw in all the way and the car does not die then the carb could be getting weak. Not necessarily time to rebuild, but just take note. Adjust the air/fuel mixture by backing out the screw several turns and then slowly turn it in until you hear the idle of the engine go down then stop and back out the screw a turn to a turn and a half. This is usually about right. Out is rich on a carb. Its kind of a feel thing. You want to adjust the air/fuel mixture so the engine idles as high as possible. Always make sure the idle is around 500 - 800 while you try to adjust the air/fuel mixture. If the idle goes higher then adjust the idle back down to 700 or so and adjust the air/fuel again. If you try to adjust with a higher idle you wont be able to tell the engine speed diffence. Oh, also make sure the engine is completely warmed up before you try to adjust.

    If you are having after run (dieseling) this is caused by the engine idle too high or the engine is running too hot. These are the two causes of this.

    Hope this helps
  3. hujibwa666

    hujibwa666 Veteran Member

    Dec 18, 2001
    Rochester, NY
    You'll probably get in trouble for the language if an administrator or someone sees this. Do you have a vacuum gauge? I heard you can use them to tune the carb. Adjust the jets until you get the highest reading. How is the engines tune as far as plugs/wires/cap/timing etc. are concerned? What do you mean when you say it spits up gas? Do you mean it backfires through the carb, or it physically dumps gas on your engine? Is it all original? Carb and engine type would help. I like to adjust my mixture screws with the air cleaner assembly on the car, as it will slightly richen when everything is together.

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