I have a mountfield mower from B&Q with a briggs & stratton engine in it, It starts up ok then starts chugging putting out black smoke, engine running arraticaly then stalls.
I take out the spark plug & it's realy black so i clean it up & the cycle starts again.
It will only run for about 2 minutes between cleening the plug each time.
I've cleaned the air filter & changed the oil, does anyone know what could be causing this.

dave.36, June 2012

Hi dave I have the same problem writhe same lawn mower from the same shop. I have to push the petrol primer button on the side to keep it going with would suggest that petrol is not being sucked or pumped through at all. Do these things have petrol pumps. I initially thought that it was a fault on the carburettor which I haven't explored yet. Will mean a strip down though and a clean. Sorry cant help really but if u find out let me know.

Ian, July 2012