Lower unit driveshaft slop

[Benny67]

I'm doing my water pump on my alpha one drives. Upon disassembly I notice a slight play (vertically) when I removed all of the water pump parts.Maybe a mm or so...not much but enough for me to question.

I also noticed that when I spin the driveshaft with these items removed, there appears to be some noise coming from the lower casing. When I pull up on the shaft slightly the noise goes away. Keep in mind the noise is minimal and there is no oil in the drive.

I am assuming that when the pump assembly is installed it must raise the driveshaft slightly and eliminate this noise? or is there a clip or space missing or worn in the lower unit?

Any suggestions or things to look for?

If I pull slightly up on the shaft and shift into gear it sounds quiet. if I just shift it and spin the shaft you can hear the noise.

Is this normal? The drive appeared to work fine last season and the oil that came out was clear with no signs of water.

 

[Bt Doctur]

the MC1 drive had the driveshaft preloaded with the spring pin in the driveshaft to push down. the later drive eliminated this pin. these gears are cut so the torque pushes the driveshaft upwards to set the gear clearance. what you describe is perfectly normal.

 

[Benny67]

As I was writing this I was thinking about the pressure created when the shaft has a load on it causing it to rise because of the way the gears are cut...it's gonna want to climb up the vertical gears.

The noise I was hearing sounded like a much lower sound when you have a shift cable out of adjustment...makes sense now.