| wimkever |
Sat Jun 01, 2019 2:06 pm |
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This is about my '67 beetle, totally stock 1300 SP engine. 30 PICT-1 carb.
After a cold start the idling is very slow, but it doesn't die. After take off I have the impression it runs a little rich
During warm up the idling rpm is increasing. After about two minutes when the choke is fully opened, the idling is a bit fast. (I didn't measure the rpm.)
I thought it should be the opposite, at least fast idling after a cold start.
As far as I can see, the choke is operating as it should. After warm up the engine runs very nice, good torque and top speed.
Suggestions what might be wrong are appreciated. |
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| mukluk |
Sat Jun 01, 2019 2:54 pm |
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Sounds fairly normal to me. Upon a cold start, a carbureted engine will often idle near or below the same speed as a normal warm idle, gradually increasing in speed as the engine warms and the throttle is left on the high speed idle cam. Tapping the throttle will allow the choke element to move the high speed idle cam, resulting in the throttle closing slightly to a lower step on the cam and reduce the idle speed.
Low idle speed during warmup is due to poor atomisation of the fuel. As the engine and intake warm, this improves and alters the mixture. Having good working carb preheat and intake heat risers will help minimise running issues. |
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