Perhaps a loose flap of liner material within the carb fuel supply hose intermittently interfering with fuel flow? Are your carb bowl vent lines properly routed between the side of the float bowl and bale and not blocked or kinked? Remove the air filter, reach in with your finger, and see if the carb piston is free and has no sticking tendencies? Could a periodic vacuum or back pressure somewhere be influencing your fuel flow to that specific carb? Sounds like you have checked most everything. This is a toughy!
ps -- Have you run your EGT plot past Mike Busch at Savvy Aviation?
David Heal - Windsor, CA (near Santa Rosa)
EAA #23982 (circa 1965) - EAA Technical Counselor and Flight Advisor; CFI - A&I
RV-12 E-LSA #120496 (SV w/ AP and ADS-B) - N124DH flying since March 2014 - 740+ hours (as of Mar 2019)!
through June 2019.
Last edited by DHeal : 09-17-2017 at 03:09 PM.