1986 90hp Merc pwr of twr lower unit disassembly

[Bakilby]

Hello,
I am trying to rebuild the lower unit on my 86, 90hp Merc twr of pwr.
I have removed the prop shaft and replaced all seals all bearings are in tact.
I am now in the process of removing the drive shaft, I have removed the wtr pump and can see the bearing from the top and I have removed the nut below the planetary gear on the shaft yet no about of tugging, wiggling and cursing sees to get it to free.
Any suggestions?
PS Reason for rebuild? it would not retain low unit oil and when I removed the prop shaft I found two bearings resting between the teeth of the planetary.

 

[jimmbo]

I will assume you mean Pinion Gear, not Planetary Gear. Once the Nut holding the Gear to the Driveshaft is removed, there is nothing but some friction of the splines holding the gear on. You say you found some pieces of Bearing in the gears? How do the Teeth on all the Gear look? If the Bearings caused the assembly to stop turning, the Splines on the Gear and Driveshaft may have twisted and that is why you are having difficulty getting them apart. If the Gears and Shaft are damaged, it gets expensive to replace the Gears as shimming is required
You might be better off getting a used Gearcase in good condition.

 

[Faztbullet]

If they were round ball bearing about 3/16 dia these are prop shaft pin bearings.

 

[Bakilby]

I will assume you mean Pinion Gear, not Planetary Gear. Once the Nut holding the Gear to the Driveshaft is removed, there is nothing but some friction of the splines holding the gear on. You say you found some pieces of Bearing in the gears? How do the Teeth on all the Gear look? If the Bearings caused the assembly to stop turning, the Splines on the Gear and Driveshaft may have twisted and that is why you are having difficulty getting them apart. If the Gears and Shaft are damaged, it gets expensive to replace the Gears as shimming is required
You might be better off getting a used Gearcase in good condition.

Yes, pinion gear, the ball bearings were in good shape and so are the gears.
The assembly never stopped functioning, it just wasn't holding gear lube. As for the pinion gear? should I be able to work it off with my hand?

 

[Bakilby]

If they were round ball bearing about 3/16 dia these are prop shaft pin bearings.

This prop shaft does not have any bearings. I am suspect that they came from the shifting spline shaft or the drive shaft.

 

[jimmbo]

At the front of the Propshaft, there is a Hole, that the shift plunger goes in to move the Clutch Dog. 3(I think) balls go in there to provide an antifriction friction surface for the Plunger when the Propshaft is spinning.

This is not the case for your engine but the Propshaft assembly is typical for Merc in that power range. #8 shows the ball bearings

 

[Chris1956]

Don't you already have enough stuff apart to replace all seals? The driveshaft seal is in the waterpump base. The shift shaft seal goes in from above. You have the bearing carrier out, so you can replace the oring and propshaft seals. Why take it apart more?

 

[Faztbullet]

Here is your gearcase...number 49

 

[Bakilby]

This prop shaft does not have any bearings. I am suspect that they came from the shifting spline shaft or the drive shaft.

Sorry I was mistaken. I found where the 3 ball bearings go...lol
And yes, I found the roller bearing on the prop shaft. all bearings seem to be ok.
I have come to the conclusion that if I need to replace the roller bearing on the drive shaft I will have to take it to a shop. I do not see any issues with that bearing either. I guess Im going to put it back together with those 3 ball bearing in the proper place and see how things go.