09-10-2024, 11:05 PM | #1 |
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Join Date: Jul 2024
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Cold start issue
Old Q-jet 1971. Runs good idles good starts when warm right away. Cannot get it to start cold without a tiny sprits of fast start. Carb rebuilt , settings double checked. There is some primary shaft play but it returns to 650 rpm when I let of the throttle. Is rebushing the shafts really gonna fix this? It doesn't seem like that little bit a vacuum leak would have that much negative affect with choke on during cold start. Anybody got any ideas? Accelerator pumps down both holes (4MV) , no hesitation when the throttle is blipped.
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09-10-2024, 11:56 PM | #2 |
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Re: Cold start issue
When you first pump it to give it some fuel and set the high idle, is the choke closing all the way?
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09-11-2024, 12:34 AM | #3 | |
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Re: Cold start issue
Quote:
Does the OP have the original cold start system, thermostatic air cleaner, riser, divorce choke and such?
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Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assembly kit for restoring the (a) truck from the ground up. My build thread, and more on the assembly kit https://67-72chevytrucks.com/vboard/...d.php?t=730025 |
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09-11-2024, 07:49 AM | #4 |
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Re: Cold start issue
If the choke is closing all the way, my first thought is metering well plugs are leaking..
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09-11-2024, 09:11 AM | #5 |
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Re: Cold start issue
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Today, 10:22 AM | #6 |
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Re: Cold start issue
Re-adjusted choke arm, it may have been a little off but blade closes completely now. Truck started. Later that day (7 hours) truck started. Today truck no start. It's gotta be combo of 54 year old thermosatic coil and worn primary throttle shafts. It takes a long time before the coil will let the idle speed drop. The truck runs great after it starts and starts right up when warm.
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Today, 11:55 AM | #7 |
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Re: Cold start issue
Describe your cold start procedure.
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Today, 11:57 AM | #8 |
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Re: Cold start issue
Truck in neutral gas pedal to floor, let pedal up and turn key.
Last edited by BDC90; Today at 12:07 PM. |
Today, 12:18 PM | #9 |
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Join Date: Aug 2009
Location: Bowser
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Re: Cold start issue
Pump it twice.
Once might not deliver enough fuel. Another thing that helps is more timing. What’s your initial timing set at? |
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