wont rev fast
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wont rev fast
I have a 1976 f100 with a 360, man. trans.4x4 I have replaced all fuel lines and pump, the distributer, the carb has been rebuilt, and timed over and over, replaced all vacuum lines( and hooked them where they were), changed plugs and wires, changed vacuum advance, and made sure I was getting good vacuum from the carb,when the engine is running it idles fine and if you depress the gas pedal slow it will rev, but if you try to rev fast you can hear a sucking sound from the carb and it almost dies. anybody got any more ideas,
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I have a Motorcraft 2 bbl, the original carb, and if I get it to a high rev speed it will try to backfire through the carb. I know I don't have a vacuum leak, last night I took a propane torch with the flame out and gas on and went around all the vacuum hoses. Tonight I'm going to start adjusting the fuel air mix with more fuel
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Lead Driver
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As said above, i would suspect the accelerator pump. when the truck is off climb up there and manually work the trottle and whatch if the pump is squirting fuel in... if not, then theres your problem. Also is it a backfire? or a lean pop? A lean pop is pretty self explanitory, the engine is starving for fuel and it pops. If thats not it.. id check valve timing.
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From: Austin, TX
Sounds like an accelerator pump issue. Hairyboxnoogle is pretty much right on target. With the truck off, take the air cleaner off the motor and look down the throat of the carb. Pull the throttle back, and you should see two good streams of gas shoot onto the venturis in the carburetor. If not, your accelerator pump could have a ruptured diaphragm or a linkage problem.
Check your timing as well. As for the sucking sound, that's somewhat normal if you stomp on the gas, but spray for vacuum leaks to check. My money is on the accelerator pump or float height.
Check your timing as well. As for the sucking sound, that's somewhat normal if you stomp on the gas, but spray for vacuum leaks to check. My money is on the accelerator pump or float height.
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I know that sucking sound hes talking about. Its not the typical healthy sound. Its that sound you hear when the carb doesnt have enough fuel. Check your float level, filter, look for kinks in the fuel line, maybe even the pickup screen in the gas tank or as noted maybe its the accelerator pump. At least you know its a fuel delivery problem.
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well I checked the float level with the little ruler that comes with the rebuild kit and the float was to high, I changed it to the right height 31/64" , i went around the vacuum hoses with the propane again, Then I ajusted the fuel/air mix a little at a time all the way to 5 turns each, and timed it again, still there is no change, there are two steady streams of gas when you hit the gas so its getting plenty
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