hi, im new to rc cars, don't know much about them or the parts. just bought a shengqi hummer from nitrotek.co.uk. everything was fine whilst running in on first tank, then it cut out and i couldn't get it started again. my dad said to clean or buy a new spark plug but i cant see anything wrong with it as its still sparking. just wanted to know what you guys think and if there's anything else i can try to get this engine going.