Hi, I have a 4 year old Mountfield rotary self-propelled mower powered by a Briggs and Stretton HP470 engine. The model number on the engine is 10D902. I cannot get it to start, so far i have emptied the old fuel and oil and replaced with new, removed the air filter, cleaned and soaked it in engine oil then wrapped it in a cloth and squeezed until no more oil came out, cleaned the spark plug with a wire brush, put it all back together again. It now will not start. When i pull on the cord it recoils back so fiercly it felt like i'd broken my hand. With the spark plug out, when i pull on the cord it feels smooth, with the spark plug in it doesn't. I left the spark plug out pulled on the cord a few times and i've left the spark plug out for over a hour thinking i'd flooded the engine, but still no difference.
Any help appreciated

Mark, March 2008

Thanks John and bg. Left it over night, tried it, it now starts first time, everytime and run smooth, i must've REALLY flooded the engine with either oil or fuel.

Mark, March 2008

No, not banged it, i had it going for about 10 seconds, it didnt run as before ie engine speed not constant. I stopped it, now cannot start it again.

Mark, March 2008

Have you hit anything with the mower ..you might have sheared the pin and that would cause a sharp recoil because its out of timing

bg, March 2008

Hi John, thanks for your amazingly fast reply. When you say tip some raw fuel down the plug hole, where do you mean. Sorry.

Mark, March 2008

Just wondered if you have tipped the engine on its side at some time - maybe to check the blades or something? This causes too much oil to be at the top end of the engine and gives the impression of excess compression - hence the sharp recoil. No worries, this will return to normal once the engine starts. Check for a spark, tip some raw fuel down the plug hole and try again. It helps if you can heat the plug up, too. I use a compressed air line down the plug hole to clear things out when this happens, pulling the starter cord at the same time. If the plug appears wet, you've flooded it but be patient, dry things off and it'll go before too long.

John, March 2008