1982 70 hp mercury, 3 cylinder outboard- - -question on verticle play in driveshaft

nydon

Recruit
Joined
Nov 1, 2016
Messages
5
Hello, I'm replacing the water pump, including the base. In the process of removing parts I noticed what seems to be excessive play (up & down) in the drive shaft that connects with the engine. The upper bearing that sits below the water pump base feels very smooth and the pinion feels okay as well when I rotate the whole assemble, so I'm not really sure there is a problem here since the upper bearing inner race is positioned so that the shaft is free to lift away (up) and the pinion below that is bolted to the end of the shaft is lifting with it away from the mating gears below; but then again what holds the assembly in place to maintain tolerances with the gears? Motor has always run perfect, just had my water pump fail as far as i can see. Any help would be appreciated.

Thanks
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
I do not believe there is a problem.---It is all held in the CORRECT place by the lower pump housing.--Your opinion may be different.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,589
The driveshaft should have the preload pin in tip and that's whats hold it in place....
 

nydon

Recruit
Joined
Nov 1, 2016
Messages
5
Thanks for responding, it sounds like this is normal. I've read through the repair manual several times and while they do talk about settings for clearances on the output shaft and pinions, there is no discussion about any tolerances or settings for the vertical drive shaft to control its movement upwords, other than placement of shims under the bearing to get proper downword clearance with the pinion gears. I agree the water pump setting above the bearing will limit some vertical movement of the shaft and the preload pin on the tip as Faztbullet advised. Not sure how all that works to control movement to a couple thousanths , maybe I'm overthinking this.
At any rate unless I hear anymore I'm putting the new pump back in and hope for the best.

Thanks again
 
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