I'm having an issue with high CHT in cruise.
When I start the plane and take off/climb, cowl flaps open, FT/rich, CHT is 360-380 in climb, pretty normal (OAT = 92). When I level off and run 25/25, if I close the cowl flaps the CHT's on #1, #3, and #4 are all over 400, #4 touching 450. Running with the cowl flaps wide open gets them down ~ 390, so I left the flaps open and landed.
I have just fixed the top engine baffling so that it seals correctly.
Is there something in the bottom of the cowling that I should be looking for? Seems like the airflow with the cowl flaps closed is obstructed or somehow compromised.
This is a new engine with ~20 hrs since overhaul but I would have expected the cylinders to be broken in by now with temps in a normal range.
Mark Jackson
M201 N201TK KAXH