Re: mercury lower unit,prop shaft play
Your spare unit should be 1969 or 1970 model off a 4 cylinder 65 or 80 hp. This unit uses a solid roller bearing under the water pump and does not use a preload pin in driveshaft. The preload pin is not to hold shaft tight ,its there it preload the upper driveshaft bearing(cone type). Also the prop shaft will have a step in it at the carrier instead of a taper as it uses a different style prop washer and a coarse thread prop nut. Also side to side play is normal as prop goes thru a needle bearing, you should be able to "feel" the side play be not notice it with you eye. The plastic couple sound like a reverse locking cam........
.i also have a spare lower unit.guy i bought it from toled me it will fit merc 850,but water pump is different type(46-37433) ,shifter coupler is plastic.also drive shaft doesnt have pin on top and prop shaft has thick tread for the prop nut.can u help me identify this model?just want to know what type of water pump replacment i should put.
