I have a 2010 Carboncub SS. Serial number 0126, 550 hours TTSN.

At 350 hours cylinder #3 had low compression, 50/80. Turned out to be a burned exhaust valve. I pulled the cylinder and had it reworked by a good engine shop. It is doing great with 200 hours on it and has perfect compression. The cylinder was inspected, new exhaust valve, lightly honed and new rings installed.

Now I have two other cylinders with low compression. 45/80. I never lean excessively, change the oil often and do not fly the plane hard. Fuel burn went up to 8.7 gph.

This time the compression is leaking past the rings and very audible through the breather hose. Also the oil got very dark over the last few hours and oil was getting past the front crankshaft seal.

I plan on pulling the 3 original cylinders and taking them to the same well known engine shop.

Any thoughts or others with similar problems? Thanks