Ah, the YS-11. When this model first came out it caught a lot of people out like that; not flown it for a while, but it was always the port engine, as I recall. Best advice I can give is ****, you really need to follow their procedures closely; at the time I cam across these comments (from one of the AFG team) which was useful guidance:
"I was part of the AFG YS-11 design team (aside from flying real YS-11's). The AFG YS-11 is designed like the real plane. You CANNOT advance the throttles abruptly during takeoff or else you'll blow the engine. This is a characteristic of the real Rolls Royce Dart 543 engine.
You CANNOT turn off the autofeather in the YS-11, because that is an automatic feature. The "feathering" indication that you see when you veer to the left (or right) during the takeoff means that you've already "blown" the engine and it has feathered (that's exactly how it's supposed to work).
The way to do it is to advance the throttles s-l-o-w-l-y to slightly less than 35 psi torque. Let the engine parameters stabilize (meaning the needles stop fluctuating), then again s-l-o-w-l-y advance the throttles to the takeoff setting. Take note, you DO NOT advance the throttles to the absolute full forward position (another "blown" engine). This is how you do it in the real YS-11. There's a better description of the takeoff technique in the readme file."
Persevere, it is worth it. Happy flying.