I was at the field one day and one guy was "breaking in" his engine.

He babied it to the point where he would not allow the engine RPM to go above about 4000 RPM (using a Tach) for at least two tanks. He was watching the RPM and the throttle setting to the point where it was really difficult to watch him do it. My reasoning there was that I had recently ran an engine in on my front lawn (the plane was tethered to the ground and I ran the engine up through at least two tanks of fuel.. maybe three). My technique was full throttle with blubbering rich HS needle setting, with occasional excursions to lean for about 10 to 20 seconds, followed by blubbering rich settings.

So far, I've not had an engine that gave me any problems at all. That included both an OS four stroke and numerous OS two strokes.

The guy that babied his engine had lots of problems getting it tuned properly and getting it to perform. His excuse was that it took several gallons of fuel to get it to run right. Mine ran right from the very beginning.. in fact, I would feel comfortable flying it right out of the box with the needle set somewhat rich.... quite a bit rich, but flyable...I'm sure you know what I mean.

Now, these were mainly OS AX series engines, with a couple of FX and one or two SF engines, and one Super Tigre 75's that always ran just fine, but leaked fuel all the time. I did have a few Evolutions, but those were a disaster and I gave them away. I could not get them to run well enough to fly no matter what I did.

CGr.