78 scotts wants to die when leaving a stop
- Thread starter trevor6
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CheemsK1500
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There's a lot that could cause that. Is your truck gas or diesel?
If it's a gas truck, it is likely either going to be a carburetor or ignition timing related issue. It could be something as simple as a clogged fuel filter. Im speaking in very general terms. As for diesel, I have no idea.
If it's a gas truck, it is likely either going to be a carburetor or ignition timing related issue. It could be something as simple as a clogged fuel filter. Im speaking in very general terms. As for diesel, I have no idea.
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fast 99
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Start by checking basic tune up items. Could be lean by numerous causes.
squaredeal91
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Yeah makes me think of float level. But usually it would stumble or die when stopping as well
75gmck25
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We need to know the know the exact carburetor, but they all work similarly. Also verify that ignition timing is at factory settings (probably 4 or 8 BTDC, or up to about 12 BTDC if you want more power). This simple change might fix your problem.
Moving the vacuum advance to full vacuum port on the carburetor may also help because it advances the timing more at idle.
It sounds like the transition from idle circuits to cruise is not correct. At idle you are running off the circuits controlled by the idle mixture screws, but as you slowly accelerate you uncover the transition slots at the butterflies and the carburetor moves to the cruise circuit. If it’s a Quadrajet or Edelbrock the rods may also start to rise up out of the jets and increase fuel flow.
If you turn over the carburetor, the Transition slots should look square-shaped (they are actually long and thin) when the butterflies are at idle. You adjust that position with the carb idle speed screw when the choke is completely off and the linkage is at warm idle. Then mount the carb on the engine and adjust the idle mixture for best vacuum. Try to leave the idle speed screws alone so you don’t screw up the transition slot exposure. The point is to not let it go too lean as you move from idle to light throttle.
You can also increase the accelerator pump shot to bridge the transition with a bigger shot of fuel. If it’s an Edelbrock you can also use different step-up springs, but this is usually used to fix a part-throttle bog. The step-up springs control the transition of the primary rods from cruise (lean) to power (rich) mode.
Moving the vacuum advance to full vacuum port on the carburetor may also help because it advances the timing more at idle.
It sounds like the transition from idle circuits to cruise is not correct. At idle you are running off the circuits controlled by the idle mixture screws, but as you slowly accelerate you uncover the transition slots at the butterflies and the carburetor moves to the cruise circuit. If it’s a Quadrajet or Edelbrock the rods may also start to rise up out of the jets and increase fuel flow.
If you turn over the carburetor, the Transition slots should look square-shaped (they are actually long and thin) when the butterflies are at idle. You adjust that position with the carb idle speed screw when the choke is completely off and the linkage is at warm idle. Then mount the carb on the engine and adjust the idle mixture for best vacuum. Try to leave the idle speed screws alone so you don’t screw up the transition slot exposure. The point is to not let it go too lean as you move from idle to light throttle.
You can also increase the accelerator pump shot to bridge the transition with a bigger shot of fuel. If it’s an Edelbrock you can also use different step-up springs, but this is usually used to fix a part-throttle bog. The step-up springs control the transition of the primary rods from cruise (lean) to power (rich) mode.
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