Hello. So I am kind of new to this hobby, had a nitro car when I was younger and had great fun but got too busy with life to continue it. Now I have had a bit of time I decided to try to rebuild my old car. It hasn't ran in 10 years so I completely stripped the engine and cleaned and re oiled it.
I just tried starting it for the first time and it was going fine, sat at idle for about 5 mins then all of a sudden the revs started to increase, I tried to stop it by blocking the exhaust but the revs just kept climbing, the car couldn't be stopped I just had to wait for it to run out of fuel. In a car I think this is called a runaway. When this had finished the engine just sat smoking from all of the heat build up.
My question is what could cause this and how to I avoid it again? Fortunately it had no wheels so didn't go crashing through my fence. Sorry if this sounds stupid.