about the castor fuel......... i dont know how long this engine has been around or what fuel was running in it before i bought it. is it good that my starter, any time, sometime struggles to turn it over. when i stick the starter on the spinner, the starter is actually slipping on the spinner. it will turn it over if i put the engine at the bottom of the compression cycle, (bottom i think, just the most travel on the prop before it reaches the next compression), and stick it on, it will start it.

i will change the fuel and see what happens