6.5 Briggs and Stratton stops when mowing on a slope?

Some Brigg's and Stratten motors have an oil level switch. When you go on a slope if it is really steep the oil level switch will think there is no oil in the motor so it will shut off. If you have that steep of lawn your best bet is to get a lawnboy lawnmower because they don't have that problem - they use mixed fuel.