simplicity

I'm looking for bearing type/size used to this part 1676278SM Arbor Shaft & Bearing Briggs and Stratton OEM. I need to replace it

The clutch / brake when released cuts out the engine. I have the seat switched jumped and the two switches activated by the clutch/brake arm work fine and tested good. Tearing my hair out. Anybody know why or have a wiring diagram? Cant find one anywhere!