LXhoweller

I have ordered some, they should be here Tuesday. Thanks for all the help by the way

Yeah working perfectly. I think I may have worked out a possible cause. The seal between the exhaust and the engine has split, I found part of it outside, I can shine a light straight through. I think it's possible that when this broke the engine just kept pulling air in making it jump in revs. Thats the only issue i found with it so far mechanically

Okay I'll try again later when I have chance. I know that can rev higher when running out of fuel but this was more than that. I genuinely thought it was about to explode by the screaming noise it made

That tube idea is a good one never thought about that. It was about to run out of fuel but that was only convenient, it could have done it with a full tank I think. I hope what I am trying to say makes sense. If you youtube diesel runaway that is essentially what happened to my RC car. The runaway only lasted 20-30 seconds but that's just because it ran out of fuel, if it had more fuel it would have lasted longer. I did try to cover the exhaust to stop it but that wouldn't stop it, the pressure from the runaway was so high it just pushed my finger off

I will also add that on inspection after it had cooled there was alot of greasy residue, I believe from the fuel, around the base of the engine and on the pull start. I don't know if this is from a leak or just from me spilling some fuel

Okay I will try stopping with the carb next time. Fortunately I only quarter filled it for first start and alot if it was gone. It only ran for about 20-30 seconds, the carb was in its idle position with about 1mm gap. Not sure what engine it is sorry, but the car is a thundertiger tomahawk st. For fuel I am using a brand new bottle of 25% nitro. I remember it being fiddly before but I've never experienced this before. Can I fix a bearing leak or would I have to replace it. Thanks Alex

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.