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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: donovan51084 on December 17, 2006, 02:50:00 pm
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ok i have a 74 k20 with a just overhauled 350. it is .060 over and has 2.02 heads ,480 lift cam, and a performer rpm intake and a performer 750 carb...i have driven it about 1000 miles since the rebuild....my problem is when i take off from a dead stop the engine starts sputtering to the point where i kind of have to "feather" the gas pedal so it wont die..once i get going about 15mph+ its fine and doesnt sputter at all...it also does it if im going slow down a dirt road... i replaced the plugs and checked all the wires no problems there...timing is fine...the carb im running i have had some problems with like the floats sticking when i hammer down on it...so my question is does this sound like it could be a carb problem or something else??
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You said your timing is fine but are you sure your spark advance is working correctly? It definitely sounds like you need to overhaul that carb and recheck your settings. Did whoever rebuilt the engine degree in the camshaft?
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yes the cam was degreed how do i check my spark advance? i would wonder if a 750cfm is too big for my motor but it worked pretty good untill now..i guess i know what im getting with my christmas bonus...
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Well do you have an HEI or Conventional distributor?
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hei
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You can check the advance with a timing light. Have someone rev up the motor while you look at timing marks. If marks move during acceleration, advance works. If it stays the same, well......
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i had my buddy rev it up and i checked the advance and it seems fine...i was looking around a couple of other posts and i was thinking maybe its the accelerator pump.. it really feels like the carb has a "flat" spot when i take off...does anyone know how to diagnose one of these on a edelbrock performer 750?
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With the motor running or not look down into the carb. Hit the throttle and you should see two streams of fuel squirt into the carb. If they do, your accelerator pump is working, If not that is your problem. If you need more help let me know.