Vibration

Combination of a nervous pilot and a sticky lifter. I put some MMO in the gas and oil and it smoothed out. Funny, I had totally forgotten about that! I also had a valve stick - hard - in 2017 and the jug was removed and overhauled. That might have been an early warning sign.

I grounded the plane today because the vibration sounded like a knock. Mag drops, static rpm, oil pressure all normal. But there is a definite knock sound that seems to be on one cylinder. A local A&P is looking it over this afternoon. I'm not going to fly it until we get this figured out.

Larry
N99340