ORIGINAL: Airplanes400
Why use a bench to run or break-inyour engine? Just put in on your plane, make a few quick adjustments to the low & high end so you have a smooth transition, set it a little rich on the high end, then fly your plane. I've been breaking-in engines in the air for the past 20 years. There is no need to "bench-run" an engine. It only annoys everyone else who is flying. It's loud and obnixious and not necessary. If you can't adjust an engine to run smoothly in less than 5 minutes, then you don't know what you're doing.
Well, that's your opinion, and you're certainly entitled to it.
However, most engine manufacturers recommend some bench break-in, as do many of the guys I know with 20+ years of experience. Our club has a break-in bench set far away from the flight line and picnic tables so anyone breaking in or tuning an engine will not bother the rest of us. It's also been used as a test stand to debug glitching and other radio problems while the engine is running.