Ate you perhaps talking about the starter switch?
Disconnect battery, disconnect wire to start switch, center trans shifter. Have new gasket on hand. Relocate choke, remove cover bolts, lift up, front first, then rear slowly, there is a small spring towards back, usually stays put, but can stick to cover and drop in trans. Clean cover and deck, lay new gasket on, fold tabs of keeper down, remove nut, remove switch, install new one and gasket, nut, keeper, put cover back on, bolts, choke, wire, battery. If this is a 5 speed, you had to remove shifter nut and leverage shifter off tapered, keyed shaft prior to cover temoval