I have a Hayter 53 Pro lawnmower with a briggs & Stratton Intek edge 60 engine. This starts fine from cold and runs well. However, when I change the grass bag (up to 10 times a session) it takes around 1/2 dozen pulls on the starter cord to get it going. SO as you can imagine this is driving me mad.

It sometimes backfires which indicates maybe it is running too rich. I can't find any adjustments on the carb itself (not obvious anyway). It has had a new air filter and been serviced.

Can anyone give me a bit of help please to sort this out. I have an older Hayter Hunter 54 which is falling apart and always starts first time, so this is even more fustrating.

Ian

Check the amount of lift between the intake and exhaust valves. Contact Briggs if one is low. This may indicate a bad cam.

Suggest checking and adjusting valve clearance. PROBABLY 0.004" 4" after TDC (power stroke).

Backfiring suggests a timing or valve issue.