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Old 02-13-2016, 10:17 AM
lippy lippy is offline
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Join Date: Apr 2012
Location: Bay Area (Peninsula), CA
Cobra Make, Engine: ERA 427, 427/487 side-oiler
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Quote:
Originally Posted by Grubby View Post
Stumble = Lean

You need more fuel. At highway cruise you are likely not into the main metering, so changing jets wouldn't help.

You are likely in the transition zone from the idle circuit to main metering.

Tell us what rpm it occurs.

John
I found that my light-throttle cruise mixture was affected by both the transition circuit and the primary jet, but you have a good point.

You should go through the basics first: ignition, idle screws, throttle plate position (with carb off) so transfer slot is properly exposed, and measure vacuum so you have an idea what power valve to use. You need to make sure all those things are nailed down and if you still have the problem then add some main primary jet.
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