I just flew a GP Easy Sport .40 for the first time today, and had an OS .46FX up front. brandnew, a slightly on the rich side.

I had the feeling the plane could use some more power now and then. I also felt the FX.46 hasn't full potential.

Now, how many tanks must I go through the get a performance increase, and can set it leaner.

I have 2 tanks on it now. I tried to set a leaner in the end, but then this would happen, when I moved from idle to full throttle:

The engines speeds up, although not immediately (short delay?) than goes to full rpm and then suddenly starts to slow again, when throttle full open. So a set it back richer, the "slow" response was still there but the rpm drop wasn't.

What to do next ?