Sounds to me like you're running way lean. You have to remember that the fuel does three things, it lubricates, it burns AND IT COOLS THE ENGINE. If you're getting that hot and using a smaller prop overrevs the engine, richen it up and try again. You could also add some alcohol and oil to what you have and try it as well. By adding enough oil and alcohol to double your quantity, you will reduce the fuel to between 3 and 5%.