I have a Morrision 500 with an original 3hp Briggs and Stratton engine on it. I'm wanting to replace this engine with a new one, I was wondering if anyone knew what size drive shaft I need to get on the new engine. The ones I'm looking at come with both 19 and 20mm shafts.
Looks like it may be the same crank as a 3.5 Hp ,if so it will be 19mm or equivalent 3/4 inch.
If you have the 3 hp engine just use a shifter on the crank then measure the shifter opening ,if you don't have a big enough shifter cut some paper the same size and measure that.