Uhg! Just received the following email from our trusted repair shop here in NY.
"Cylinders #2 & #4 have a ring step at the top end of the cylinder wall when the piston is at its top of its travel and although the compression test showed 63 lbs, the pressure dropped 25 lbs when the piston was moved slightly, Then you could hear the pressure loss coming through the crankcase.
Cylinder #6 failed the test with a reading of 36 lbs leaking mostly past the exhaust valve. I recommend removing all three cylinders for evaluation & repair.
We are also going to have send the magnetos in for overhaul due to the amount of time on them since last overhaul, as well as per an "AD"."
We still have about 375 or 3 years before TBO.
Any insights or guidance would be very much appreciated.
Thanks in advance.