I'm hoping for some wisdom / assistance in helping a friend troubleshoot a rough running engine in his purchased RV-9.
Background: RV-9, carb'd lycoming o-320, dual mags, pretty much basic setup as per vans.
Jim bought the airplane earlier this year, it was pretty new with phase I flown off. Has about ~75 hours now. Aside from some warmer CHTs, the engine had been running fine.
Early Aug, he and a friend flew to a nearby airport for fuel. On return, (in the dark!) the engine began running rough. Runs rough at higher power, seems to smooth out if the throttle is pulled back.
I am going to link to engine data from 2 flights:
First, before any issues arose and the engine was running well (this was takeoffs and landings at our local airport):
The flight where issues arose:
I am going to share the link with Jim so he can register / login and help answer any other questions. Not sure he is on VAF yet.
Thanks in advance for any thoughts / suggestions