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Old 07-03-2021, 08:51 PM
Join Date: Jul 2004
Location: White Bear lake, MN
Posts: 530
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Do the "pinch test" when at idle. Use whatever tool or fingers that will safely pinch closed the fuel line going to the carb. If it continues to run, but picks up speed before dyeing, the idle mixture is too rich. If it dies quickly and abruptly, it is too lean. You should be able to get several seconds of run, without it picking up rpm before it dies. A bit of going too rich, then backing it down, will get you to the ideal point.
I'm guessing it currently is a bit too rich, and the time at idle to get it out to the runway was longer than the in the pits testing - so it built up too much fuel, and stalled.
You can also use this method to test the top end needle setting, with point-it-up-and-down as the final verification. I'd then back off a click or two to the rich side, just to be conservative.