i have mcculloch m56 875 dwa self starter briggs and stratton engine i have just changed the blade which involved tipping machine on its side when i tried to start it ran fior couple of seconds then stopped with enormous backfire, when tried again it just backfired, there is oil and petrol in machine. waht can i dfo. have i flooded engine or is something else more sinister involved

bill, October 2012

when you tip the lawnmower on its side( to change the blade etc) you have to make sure the petrol cap is above the oil cap,( usually top of mower pointing to the right when youre standing by the handle) otherwise the oil will get into the petrol tank, drain the petrol out and refill with fresh petrol, ridiculous but true

simon, December 2012