Dave,

Today I had a chance to try a different known good regulator assembly on my YS61ST2 engine. It is not the regulator....the engine ran just as bad with it. I also had the opportunity to put the good reg on my other YS61ST2 (the one where it came from) and remount it in the heli and the engine ran fine...with or without the governor engaged. So that leaves the carb and piston/sleeve as the problem area...and those parts are very expensive and I feel it is just better to buy a new engine as this point.

The engine just does not run consistent.....leaning out when I give throttle/collective and then when you go back to hover it surges back and forth.

Thanks for your help... I guess the engine just has too much time on it?

Michael