this motor is on a 52 scag. i think it's 2009. the motor has less than 300hrs. my problem is the motor runs fine 97% of the time but it sounds like it drops a cylinder. when it drops a cylinder it runs rough and the exhaust smells like fuel or (rich) then it will start running good again nice and smooth. would this be a coild going bad? also the last few days it's been hard to start on the first crank up of the day. after it finally starts it cranks and starts fine.