I'm making plans to get my first pattern plane and am trying to decide on which engine to get. My choices are an OS 120AX and a YS FZ-110S, and an OS FS 120-SE Surpass.

I have a little familiarity with the AX series - my first engine was an AX which I still use daily, and I had a 55AX on a plane that I flew for a week or two then sold, before it really was broken in.

It's my understanding that four strokes (especially YS?) are more difficult to tune. Of course I want the most flying time as I am still new and need stick time. However I want the power, sound, and efficiency of a four stroke. Pattern pilots seem to prefer the YS because of the power-to-weight ratio, and many of them are using the 120AX as well. I listed the OS four stroke as I have had 2 OS engines and have been happy with them.

There really is no one at my field with any experience with YS four strokes. There are a number of Magnum 4 strokes, and many of them are problematic.

I really can't decide, what do you think is the best FOR ME, not just the best.

Thank you much.

Just to add: I did have some issues trying to get the 55AX running right - as did a few other experienced pilots at my field.

The plane is likely to be a Great Planes Venus II or a Piedmont Focus Sport, both recommend a .90 two stroke or a 1.10/1.20 four stroke, and the YS 110 and 120AX are the two most common engines used by pilots in these planes.