overheating issues

So I built an ft mini mustang and the motor got closes to 100 degrees when I checked it. I am using the power pack a with the Radial 1806 2280kV motor. I am also using a 3s 800mah lipo. Any ideas on why it's getting so hot and how to fix it?

Noob question. How does one determine if an esc is overheating? I am flying a ARC Pirates Eazy, fairly small aircraft, smaller that the TT. I am running it on a DYS Samguk 2206 2400kv motor with a 5x4x4 prop and a 30a Emax BL Heli esc. I maidened it the other day on 3s and it flew awesome...

I built the sparrow with a Emax MT1806-2280kv using the BL Heli 12amp ESC. I'm flying at about 2/3 throttle for 2 or 3 minutes, then it starts lagging and losing power. I bench tested with the wing off and felt the ESC and motor... both really hot. I just replaced the ESC because the prior...