FAB not installed
I chased a bad idle and a rough running O-320 carb engine, and found that running it without the FAB and filter installed caused most of the issues. As soon as I installed the FAB and filter, the engine ran "sweet", and only needed minor idle mixture and idle speed adjustments.
The engine ran well at high power, but idled very poorly. I can only assume that the airflow past the carb was disrupted enough to cause the issues. I also had a left mag issue that contributed to the problem.
NB: I was running the engine cowl off, with a bare carb. No FAB installed, no filter installed. Reinstalling both fixed the issue, even with cowl off.
Not sure if this was your issue................
Pete Hunt, [San Diego] VAF #1069
RV-6, RV-6A, T-6G
ATP, CFII, A&P
2021 Donation+, Gladly Sent
Last edited by PCHunt : 09-21-2020 at 03:06 AM.
Reason: Corrected error