Thought I needed to get another fertilizer pump when my old Honda-powered one died during corn planting. Had a few minutes after supper tonight, so I took it apart-found a stuck exhaust valve. A little Hagen Brew and a tap with a small hammer, it came loose. Stuck it back together with new synthetic oil and replaced the starter rope for good measure, seems to run as good as ever.

Why would an exhaust valve stick? Is it just 'one of those things', or can I do something to prevent it from happening again? Thought about adding a bit of 2-stroke oil to the gas, but haven't done anything yet.