While you wait for answers, we may have found some information which could help you.
Click here for Mower Hayter EngineAdding oil to mower ?
lawn mower briggs and stratton classic 35?
How can I fix Mountfield Laser Omega 46 Lawnmower?
My Briggs & Stratton 10.5 engine will start but dies after about 15 mins?
Petrol or diesel?
Briggs and Stratton SP470?