Just finished flying my Sig Senior with a new .46 Evolution. This is a engine that is suppose to be set from the factory and is already broken in. First couple of starts it wouldn't keep an idle. I had to adjust the idle needle. I actually had to go past the limiter about 1/2 turn. After that the engine ran great. Flew the plane 4 times then called it a day. The engine had great power and great excelleration. Brought the plane home and opened up the engine to see how it was wearing after the first time out. To my surprise the top of the cylinder sleeve is chipped away. Now this is a brand new engine with less than two 2 1/2 tanks of gas through it. Has anyone seen this happen before. I am going to contact Horizon hobbie to see what they say. It still has great compresion and it starts just fine. The chip is at the top off the sleeve and is about 1/2 wide x 1/4 down the sleeve. Wondering how long it will last or should I just buy another sleeve and piston for it. Thinking about going back to OS