While you wait for answers, we may have found some information which could help you.
Click here for Riding Mower HpMy Briggs & Stratton 10.5 engine will start but dies after about 15 mins?
lawn mower won't start?
westwood t1200?
Briggs and Stratton SP470?
Adding oil to mower ?
litres of oil needed in a countax c600h ride on lawnmower?