Try this as a quick experiment...

Reduce your pitch curve by 10 - 20% on the high side, and bring it up 10 to 20% on the negative so that your blades are never at quite as much pos or neg pitch..

Also, set up dual rates on your cyclic to about 80% so that you don't get as much pitch there either. These changes should only take about 15 mins. to do, and if you have another idle-up available on your transmitter (like, Idle-up 2 or 3), you could set it up there without changin your existing config.

Then try the maneuvers with these settings. Of course, they'll be a little slower, but if the engine doesn't bog, then you've found your problem (too much pitch for the power of the engine).

You can try leaning the engine, but it sounds like you have it running well. I'd try reducing the pitch a little first.

Regards,

- Ben1000