Bruce: The possible exception to that is the OS 74 AX I just bought for the Protege. I started it up yesterday, ran it about 2 minutes at a high idle, then gradually increased it to full throttle with a very rich mixture and ran it that way for another several minutes when I leaned it out for about 10 seconds then ran it down to a high idle again. Just for curiosity, I reduced the throttle trim from high idle to a very slow idle of about 1800 RPM. It stayed there idling along very nicely.

It did hesitate a bit after that when going to full throttle, but it never stalled out.

I ran it through the rest of the tank and then refueled it and put the plane in the air. It never once hesitated during the next full tank burn, and I did several touch and goes after about 5 minutes of fam-flying.

A great engine, probably an exception to the rule when it comes to new engines, that's for sure.