No gasket sealer needed as the carb and inlet pipe are sealed with 'O' rings.

I think you'll find that the .72 is too much for the Four Star 40. I flew mine the .62 for the first time today and needed 2oz of lead at the tail to balance correctly.

The .62 had no problems hauling the 4* around the sky, even when running at break-in slobbering rich.

I've head most people use a 51-56 size 4 stroke on the 4*.