Stiff shift shaft question

[SHickey]

Hello,

I needed to replace the oil seal on the shifting shaft on my 165HP 1976 MC-1 lower unit. After I split the outdrive and removed the shifting shaft bushing, I discovered the shaft bushing did not have an oil seal in place??? I replaced the bushing, oil seal that sits in the bushing, and two washers (one metal and one rubber) and put the outdrive back together.

After putting everything together, I noticed the shift shaft seems to be fairly stiff to turn. Before I installed the oil seal and two washers that sit on top of the bushing, the shift shaft could be easily turned by hand. Now with the new seal and washers I need a wrench to turn the shaft and I was wondering if that is normal??

Any input is most welcome. I have not reinstalled the outdrive on to the boat yet so if I need to take it apart, I can always do that too if I messed up something.

Here in NYS, spring is just around the corner!!

SH

 

[ziggy]

did you do the upgrade? mercruiser service bulletin 91-25 ?
i R&Red my shift shaft and bush some time ago. i remember i used aftermarket parts and my shift shaft became real stiff to turn too. mine was from poorly made shift shaft and the lever that screws onto the shaft. i did use the after market bush and seal. like the one in the s/b. but i ended up getting an oem shift shaft and shift shaft lever arm. them two parts were mis-manufactured. the oem parts worked perfect. so far the aftermarket seal has work proper too.
don't know if that helps. but for sure yer gonna have to loosen it up.

 

[Bt Doctur]

If you didnt have the seal ,you would have been losing oil. a replacement shift shaft come with the seal installed .all you need is the small rubber washer and the larger SS washer.

 

[wrench 3]

If you didnt have the seal ,you would have been losing oil. a replacement shift shaft come with the seal installed .all you need is the small rubber washer and the larger SS washer.

I believe that the OP is referring to the upper shift shaft not the lower.

Too the OP- If you hammered in the upper bushing instead of pulling it in you may have burred the hole in. If so, clean it up with a round file.

 

[SHickey]

Thank you for the responses.

The shift shaft I am referring to is in the lower unit that directly engages the prop shaft transmission. It is multiple grooved on either end to engage the prop shaft and shift arm in the upper unit.

The situation I believe that is unfolding is that when I reassembled the the oil seal into the bushing and added the two washers to the top of the shaft, the added parts have eliminated any play with the shifting arm assembly and made everything very snug.

The original bushing I removed had a thin rubber washer mounted in the bottom of the bushing but the actual oil seal that mounts in the top of the bushing was missing?? Which explains why the oil leak was very slow coming out of the water weep hole in the LU.

Last question?? When I installed the oil seal into the top of the bushing I tapped it in with a rubber mallet but it did not seem to want to go down all the way into the bushing indent so the top of the oil seal was about an 1/8 of an inch above the bushing top. When I replaced the two washers on top of the bushing I believe all of the play was removed from the shift arm. Should I remove the bushing and see if I can pound down the oil seal further down into the bushing or are they designed to stick up a little. And should the shift shaft be able to freely turn by hand or can it operate in the firm state it is in now??

​Thanks again for your help!!

 

[wrench 3]

Did you install the seal with the open end up? As with BT Doctur, I'm curious as to how you came up with a new bushing that didn't have the seal all ready installed.

 

[flipbro]

Also curious! If the seal is truly up 1/8of an inch that would definitely cause the problem.

 

[SHickey]

Thank you all for your input!!

This morning, I went back and split the lower unit from the upper unit and whacked the oil seal down flush with the top of the bushing. Reinstalled the two washers and reinstalled the lower to the upper and guess what??

The shift lever works fine!! There is a little bit of tension on it but I can turn it by hand.

Looking back, when I initially disassembled the shift shaft assembly, it was missing the top SS washer, and the rubber washer that sits on top of the bushing was broken. The bushing did not have an oil seal and the only thing resembling an oil seal was a thin rubber membrane on the bottom of the bushing. So thankfully the oil leak was marginal but getting slowly worse over time.

I will add the outdrive oil tonight and check for leaks.

Hopefully this will be the last outdrive repair I will need to perform this season!! (except to mount it back on to the boat)

Thanks again, you guys are the best!!

 

[flipbro]

You should make up a pressure tester and check it that way?

 

[SHickey]

Good idea

I have seen some interesting outdrive pressure tester set ups on this forum. I just never got around to making one yet.

My next outdrive repair will be on a 1972 140HP MC-I that needs prop shaft seals and maybe a few other replacement parts and seals after I break her open. She came off of a 21' Mirrocraft aluminum cuddy cabin monster I started to gut and refurbish. I told my wife it will be a few years until that craft is complete.

Sadly, these boats and repairs just keep me out of trouble with all the kids out of college and the house!!