carguy614
Well Known Member
Hey folks.
I call opon the vast knowledge of the VAF group for some advice.
My RV-9A has a superior O-320 and a new Precision MA4-SPA carb.My issue is high EGT temps on climbout and operation over 2300 RPM on the back 2 cylinders. The spread is nearly 175 degrees at high cruise, and as much as 250 degrees during full power climbout at sea level. I am equipped with a Sensi fixed pitch prop. Slight nleaning in the climb produces slightly higher EGT on the front 2 cylinders, and does not effect the rear ones. Carb heat makes no difference either. I suspect an intake air leak of some sort, but cannot find one. I have replaced the tube gaskets and rubber connectors, and smoke checked the induction system. No leaks. No fuel leaks thru the primer system , and CHT temps are really well balanced in cruise and very good in the climb after some effort to adjust baffling to get the temps in line.
Engine runs great, and I have no reason to suspect the probes, as they read even at 2200, and display ambient temps perfectly on my Dynon D-120. The probes are exactly 2 inches from the head on all cylinders, But I have yet to swap cylinders, as the leads are too short to do that on my plane.
I will need to do a full throttle 8000 density wide open throttle check to see how much spread I have to peak, but ceilings have been extremely low around here forever. I suspect the main jet is a bit too small, as others have commented in the archives. some have commented on uneven fuel distribution with a carb equipped engine at less than WOT.
Thought I would see if anyone has had a similar issue, and what you did to resolve it.
Thanks a million,
Chris
I call opon the vast knowledge of the VAF group for some advice.
My RV-9A has a superior O-320 and a new Precision MA4-SPA carb.My issue is high EGT temps on climbout and operation over 2300 RPM on the back 2 cylinders. The spread is nearly 175 degrees at high cruise, and as much as 250 degrees during full power climbout at sea level. I am equipped with a Sensi fixed pitch prop. Slight nleaning in the climb produces slightly higher EGT on the front 2 cylinders, and does not effect the rear ones. Carb heat makes no difference either. I suspect an intake air leak of some sort, but cannot find one. I have replaced the tube gaskets and rubber connectors, and smoke checked the induction system. No leaks. No fuel leaks thru the primer system , and CHT temps are really well balanced in cruise and very good in the climb after some effort to adjust baffling to get the temps in line.
Engine runs great, and I have no reason to suspect the probes, as they read even at 2200, and display ambient temps perfectly on my Dynon D-120. The probes are exactly 2 inches from the head on all cylinders, But I have yet to swap cylinders, as the leads are too short to do that on my plane.
I will need to do a full throttle 8000 density wide open throttle check to see how much spread I have to peak, but ceilings have been extremely low around here forever. I suspect the main jet is a bit too small, as others have commented in the archives. some have commented on uneven fuel distribution with a carb equipped engine at less than WOT.
Thought I would see if anyone has had a similar issue, and what you did to resolve it.
Thanks a million,
Chris