my briggs and stratton 35 classic engine on my partner 431 lawnmower wont start. i have taken the magneto thing off and cleaned it up and it started but when i put the airfilter back on it cut out and wont spark at all i dont know what the gap is supposed to be between the drum and magnet thing could someone please help me

Damien, May 2008

The gap between the flywheel and the coil is the thickness of a piece of thin card - such as from a fag packet. Make sure the flywheel key is in place too as the timing will be out.

John, May 2008