Well he didn't say exactly, but I know he was running a custom blend 30% heli fuel, with very high synthetic lubricants. I don't know the exact recipe. But I had planned on taking the carb apart and soaking it in WD40. He said he hadn't run it since December, so hopefully the carb is just gunked up and a good cleaning will do. If not then I'll probably have to get a new carb. I don't know. I have a 1/10 ST, but it has a rotary carb on it, and I've never experienced anything like this before.