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Clutch causes engine to stall?

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BobsBugeye

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Hello, I have a 1961 Bugeye, 948cc. I've been working on the carburetors and have them adjusted somewhat. My problem is I set the idle rpm at 1000 and when I push in the clutch the engine idle drops usually to around 700-800 rpm. Sometimes if I hold the clutch down for a longer time than just shifting the engine will slow way down and run rough and almost stall. I've never seen this before on any car with a clutch. Any thoughts?
 
Sounds like something is dragging that is not evident when the car is in neutral, which makes me think pressure plate or thrust bearing.
 
Worst case - very worn thrust bearings for the crank. For peace of mind I would take the time to measure the crank endfloat and compare it to the manual to see if it is in acceptable limits.
 
Could be the issues above OR you're actually idling on one carb or the carbs aren't balanced. When you press the clutch it is loading the engine enough to slow it down.

A quick check to check for carb balance is to take the air cleaners off and restrict the intake of each carb one at a time with your hand. If they are balanced, the engine will slow down the same amount for each. If one has a much smaller effect than the other you know that carb is not contributing as much as the other.

Note: A small decrease in idle speed with the clutch pedal down is normal.
 
I haven't had time to test any suggestion yet. But I am having trouble getting the carburetors to work properly so I will try the carb test today and see what happens.
 
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