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Old Mar 12, 2021 | 10:14 AM
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Default Question about starting

Hello! On my 79 L82 I have an issue with starting.

I pump the gas once, then twice, and on the third one I hold it down and release slowly. I crank the car over for about 3 seconds and the car fires right up. The only issue is I need to feather the gas pedal in order to keep it idling until the car is warmed up. Once it is warmed up, it idles fine, no need to feather the gas pedal. It also high idles (until it is warmed up) and I hit the gas to bring the rpms down to idling rpms. After the initial warmup (while feathering the gas) if I turn car off then restart the car just fine with not feathering the gas pedal and it fires right up. After the initial warm up, it starts just fine throughout the day with no problems at all.

I have an original, rebuilt roch carb and it seems to only be an issue on cold startup. I have to feather the gas pedal, after pumping 3 times, in order for it to warm up. Also, during this time period I have very strong fuel smells coming from the exhaust which stinks up the garage. Any ideas or help? Thank you!
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Old Mar 12, 2021 | 01:46 PM
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First does your choke work. One reason we have to "pump" the pedal at least once is to set the choke. Once it starts with the choke on it should idle high around 1500 RPM's.
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Old Mar 12, 2021 | 01:52 PM
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Originally Posted by Davoforty
Hello! On my 79 L82 I have an issue with starting.

I pump the gas once, then twice, and on the third one I hold it down and release slowly. I crank the car over for about 3 seconds and the car fires right up. The only issue is I need to feather the gas pedal in order to keep it idling until the car is warmed up. Once it is warmed up, it idles fine, no need to feather the gas pedal. It also high idles (until it is warmed up) and I hit the gas to bring the rpms down to idling rpms. After the initial warmup (while feathering the gas) if I turn car off then restart the car just fine with not feathering the gas pedal and it fires right up. After the initial warm up, it starts just fine throughout the day with no problems at all.

I have an original, rebuilt roch carb and it seems to only be an issue on cold startup. I have to feather the gas pedal, after pumping 3 times, in order for it to warm up. Also, during this time period I have very strong fuel smells coming from the exhaust which stinks up the garage. Any ideas or help? Thank you!
visually inspect choke while starting.. does the vacuum choke pull off open (opens slightly to keep running) right after starting?
releasing pedal slowly IMO does nothing..

Last edited by interpon; Mar 12, 2021 at 01:53 PM.
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Old Mar 12, 2021 | 02:02 PM
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Based on your comments, your choke pulloff is not correctly adjusted, or it may have failed.

Lars
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Old Mar 12, 2021 | 02:06 PM
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Choke seems to work. I pump the pedal once to set the choke and it opens slightly (maybe 1/4 of an inch). After the first pump (to set the choke) I pump it again to give it a squirt of gas. After that I have to feather the gas to keep it going until it is warmed up. Once the vette is warm, after high idle, I can turn it off and on throughout the day without feathering the gas. Thank you for your responses!
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Old Mar 12, 2021 | 02:07 PM
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Originally Posted by lars
Based on your comments, your choke pulloff is not correctly adjusted, or it may have failed.

Lars
Thank you for your response Lars! I am going to do some further investigating. I am going to check the choke pulloff...any suggestions what to look for?
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Old Mar 12, 2021 | 02:29 PM
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The choke pulloff should crack the choke open 1/4" as measured from the forward, lower edge of the choke plate to the airhorn wall, but set it to whatever spec you need to make the engine idle reliably by itself upon cold start. This should have been set and tested by the carb builder.

Lars
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