It’s been quite a while since I worked on mine, but from what I remember, and from
looking at the parts diagram……
-Remove the exhaust snout, gear case prop shaft cap, unhook the water line from the pump, and remove the water pump assembly,
and remove the “through bolt” holding the gear case to the drive shaft tube.
Tap the gear case down and off the driveshaft tube with a block of wood and hammer.
It seems like it’s a little tricky not to bend the water discharge tube, so be careful.
Other’s may have better advice, or memory!
Prepare to be boarded!