I've just received my brand new John Deere d-130 riding mower today 4-27-15. Everything seems perfect, runs great except for the idle; its rough a little jerky and is hinting at popping back through maybe an exhaust valve? I know the logical thing is to return to the dealer, but could this be a non issue due to the fact it is not yet broken-in (only .2 hours on the meter). Any suggestions or comments are welcome. The engine is Briggs-Stratton 22 hp 724cc V-twin cyl. (rough and uneven idle speed when idled down, maybe a spark plug going out?) Shouldn't idle be fairly smooth on this V-twin? Thanks for any advice...........