by 357ross » Wed Mar 31, 2010 2:51 pm
Hello all, I recently bought a used K&B 61 engine. When I first got it, the bearings felt super smooth, and the compression felt excellent. This engine has a ringed piston. I mounted it on a test stand and fired it up. The fuel I was using is 10% nitro, 16% oil. The engine seemed to run really strong. After about half a cup of fuel, it quit. Now it has very little compression, and even after putting after-run oil in it, the bearings feel a little gritty. My question is have I ruined my engine, or is this a part of the break-in process? Thank you for your help.