Sup guys, after leaving this thing to sit for about 2 weeks i started it up and it started smoking a good amount out of the exhaust, so i thought it would go away after the engine was warm so i let it run for like 10-15 minutes. the smoking never went away so i shut it off and started working on the brakes, after working on them i started it up and no smoke was coming out whats so ever. what would cause this? plus the smoke was pretty heavy the first time i started it.