Good engine choice!

I have a brand new Irvine .40, and it does, to me, improve on each tank of fuel. I have only ran maybe 1/4 to 1/3 gal. on mine and I'm thinking your Irvine .53 will do better each time as well.

Instruction manual for my .40 say's to always run it more rich than lean. You might want to use the same plug/fuel setup you would for normal flying as well.

Enjoy the Irvine!