hi, im a semi beginner to rc cars, but i just got a new Madforce. i did all the break in procedures, but when i try to shut the engine down, pinching the fuel line didnt work so i covered the exaust pipe and that worked maby i didnt pinch it long enough but when i was pinching it, the engine started running fast. after this, i took my car in, did my homework, all this in a period of maby an hour and a half. but then i picked up my car and this black oil looking gunk came out of the exaust. it wasnt a hole lot but i dont think it should have been in there. plaese help me out guys, i spent a lot of money on this monster truck and i dont want to break the engine [
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