Bax,

I have a OS 160 FX in a 1.20 sized Edge. I think I have enough air inlet and exit to keep it cool, but it keeps overheating. I'm running Powermaster YS/Saito 20/20 in it. Someone said it could be the higher nitro content, but I didn't think that a switch from 15% nitro to 20% would make that much of a difference. Plus, I have 2% more oil and than a 15% fuel. I thought about getting some Cool Power 15% but I wanted your opinion first. The attached pictures are of the engine in the cowl and the various cut outs for cooling. Do you think I just need to add some baffling or should I try lower nitro fuel?

Large cooling inlets and outlets do not guarantee good cooling. You must be absolutely sure that any air coming into the cowl actually passes through the fins of the cylinder. If you can see the air outlet, or there's a lot of space around the engine, then air that enters is not likely going through the fins. You'll have to make a baffle to insure that air actually goes through the fins.

That's the most common reason cowled engines don't get enough cooling. From your pictures, it looks like that's exactly what's happening.