Re: 1972 merc 650 how to reinstall lower unit help.
Right now the lower unit is probably in Fwd gear and you've got a ton of free play in the shift shaft. Rotate the shift shaft counterclockwise until you just start feel resistance. This should be Fwd gear.
Take a pair of pliers (cushioned with a rag or tape on the jaws, so you don't mess up the shift shaft splines), and continue to turn the shift shaft counterclockwise. With just a bit more movement, you should feel a "notch" and you can verify the L/U is in Neutral if the propshaft spins freely without turning the driveshaft.
Place your remote control box in Neutral as well, and reinstall the lower unit. You'll need to turn the flywheel clockwise to get the splines on the crankshaft and driveshaft to line up. This'll come within the last few inches before the L/U flange mates with the flange on the mid-section.
Note that sometimes, even with the L/U and control box in Neutral, you'll have trouble getting the shift shaft and the upper shift rod realigned. Usuallly the trouble is a little pre-loading of the shifter cable.
If you have that issue, you'll need to get the motor-end throttle cable out of the way, then disconnect the shift cable so you can freely move the shifter arm on the upper shift rod. Once everything is all realigned and the lower unit bolted back up fully, you can reconnect the shift cable.
HTH & let us know if you have any more issues with the L/U reinstall.........ed
