Need help: 1998 Mercury 115hp shift shaft will not go back into lower unit...

[TheBigSur]

Hi iBoat Friends,

I was helping my Dad with some maintenance on his 1998 Mercury Outboard (Model 115EXLPTO/Serial Number OG691795). We removed the lower unit to replace all the oil seals due to water in the gear box. After removing the cover from the shift shaft, I accidentally pulled up on the shift shaft. Much to my surprise, it came completely out of the lower unit gearbox. I noticed that it had splines on the end and it very different from my 2001 Johnson outboard which actually screws into the lower unit.

The shift shaft on the Mercury 115 is actually divided into an upper shift shaft with a "female spliced end" (which remains in the housing) and a lower shift shaft with a "male spliced end" (which is removed with the lower unit). So here is my dilemma: When I try to place the lower shift shaft back into the lower unit gearbox via it's tube (with a small hole in the bottom), it goes down pretty far and then meets resistance. When I turn the shift shaft (clockwise or counter-clockwise), it only spins in place, but does not engage the gear box to change from forward, to neutral, or to reverse. Do I have to pull the bearing carrier to re-seat the shift shaft? What do I need to do to re-install the shift shaft correctly so it will change the gears? Any help is appreciated...thank you!

 

[hardwater fisherman]

No Title

The shift cam that receives the shift rod should look like the one in the photo. It appears to me that it just drops back into place. Maybe when you feel resistance just turn the shaft slowly to line up the splines. There are many people here that can confirm if I am correct or not.

 

[Mercurylips]

I had this happen to me the first time I was left alone to do my lower unit seals. I just wiggled the shaft down into position and pressed a bit harder and it went back in. Sometimes it is better to be lucky than good. The other little cam was also out of place but my Mercury Manual saved me there.

 

[TheBigSur]

Mercurylips and hardwater fisherman...Thanks for the information. Yes, I believe that is the correct Shift Cam as the Shift Shaft has 6 splines at the end. Unfortunately, the "wiggle and push" method does not work. The shift cam has moved forward...likely due to the spring behind it??? I read a few additional posts and believe I'm going to have to pull the bearing carrier (oh what fun that's going to be!!). Perhaps then I can reposition it so that when I insert the shift shaft, it will depress the spring when I replace the bearing carrier. I was just trying to avoid this if possible. Also, any idea how to make sure that I've correctly aligned the splines so that the shift shaft correctly rotates from forward, to neutral, to reverse when I connect it back to the upper shift shaft? Honestly, this type of design is not ideal...but what do you expect from 1998, right? :lol:. I much prefer my 2001 Johnson 200 V6. The shift shaft is easy to remove with a simple screw. And then as long as you don't unscrew it from the gear box, it's fine. And even if you do, all you have to do is measure the distance it's supposed to be. Guess it's good that I'm learning different boat engines?! Like I tell everyone, I'm not much of a fisherman, but I'm becoming a hell of a boat mechanic!!! :lol::lol::lol:

 

[tommarvin]

Removing and reinstalling the bearing carrier is very hard and complicated, special tools.
Do you have a factory service manual.
I've never done this, would it help to turn the prop shaft or flywheel, or move gear shifter control
Would it help to put in forward or reverse?.
Thanks for the warning.

 

[TheBigSur]

tommarvin. Yes, removing the bearing carrier can be a pain, especially if it is seized due to saltwater as I expect this one to be. To pull it, it may require a modified steering wheel or bearing puller. Some folks have to apply heat with a torch. I may just pay my local boat mechanic shop $20 to pull the bearing carrier and then work on it. If you want to completely replace ALL the seals/rings, then you have to pull the bearing carrier to replace the large O-ring inside. So, it's going to have to be pulled anyways if I want to ensure all the seals are new. I appreciate all the advice, but I've tried everything...turning the prop shaft, the drive shaft, both at the same time, reverse (which clicks), and every other combination. I really think the cam has shifted forward and the only way to get it right is to pull the bearing carrier. I agree that a good idea may be to purchase the manual. I've been using the exploded diagrams from CrowleyMarine.com which are excellent, but agree that they don't tell you step-by-step how to remove and replace parts. Unless others have any ideas, I'm going to pull the bearing carrier and I'll let everyone know how it goes. In the future, I recommend to LEAVE THE SHIFT SHAFT ALONE on these model mercury engines!

 

[tommarvin]

If your open to boat mechanics ask him if there's a way to reinstall the shift shaft.

 

[TheBigSur]

tommarvin. Good advice...I'm definitely open to a boat mechanic's advice before I go tearing into anything. Given all the great advice, I'm waiting to see if others have experienced this problem as I would really like to avoid pulling the bearing carrier unless I absolutely have to. Perhaps racerone or boobie would have any sage advice for me as well? They were especially helpful when I had to replace my neutral shift switch on my Johnson. Once I hear back from them (hopefully), I'm going to make some decisions. I won't be able to work on it again until Thurs. I'm traveling out of town for work as well as waiting for parts to arrive. Thanks for all the great advice thus far. This is a great forum for hacks like me! :witless:

 

[boobie]

Big Sur, I'm sorry to say I don't have any Mercury experience on the newer ones.I'm just an old Omc person. See if you can find a Merc mechanic as I'm sure they're out there. Sorry.

 

[boobie]

Edit......

 

[TheBigSur]

boobie . No problem, boobie. I appreciate all your help with my Johnson a couple months ago. Once I figure this out with my Dad's Mercury, I'll be sure to close the post so everyone can learn from my mishap. That's how we all learn I guess? :lol:

 

[boobie]

Yes, please let us know how you fixed it. Good Luck !!

 

[Mercurylips]

tommarvin. Good advice...I'm definitely open to a boat mechanic's advice before I go tearing into anything. Given all the great advice, I'm waiting to see if others have experienced this problem as I would really like to avoid pulling the bearing carrier unless I absolutely have to. Perhaps racerone or boobie would have any sage advice for me as well? They were especially helpful when I had to replace my neutral shift switch on my Johnson. Once I hear back from them (hopefully), I'm going to make some decisions. I won't be able to work on it again until Thurs. I'm traveling out of town for work as well as waiting for parts to arrive. Thanks for all the great advice thus far. This is a great forum for hacks like me! :witless:

​There may be a good way to remove your bearing carrier. I had a friend that had a plumbers pipe stand with a chain vise. We used it like a large bench vise and he held the lower unit upright with the chain wrapped and firmly secured around the prop shaft. I then gave the lower unit a few firm raps with a rubber mallet and the bearing carrier came out. Essentially like the directions given in the Mercury manual. You should have a manual. If you have a good large bench vise you can do this but you will need some help. The only other difficult process is removing the bearing
carrier nut. Soak it with some break free or penetrating oil to make it easier to remove. I tapped on mine with a hammer to loosen it but that is not good with the new plastic rings. They will chip off. All well and good but then it needs to go back together. ..............

 

[TheBigSur]

​boobie: Well, I got the shift shaft back in...THANKS TO emckelvy and his most AWESOME POST from 9 years ago. Here is the link and the thread that was explained so wonderfully as to how to fix the issue: http://forums.iboats.com/forum/engi...stalling-shift-shaft-into-lower-unit?t=264376

This forum is just phenomenal. I would almost guarantee that someone has fixed your issue at some point in the past...you just have to locate it! Thanks again emckelvy...9 years later...you are the man! Have a great weekend everyone!!!

 

[dandreye]

TheBigSur:

> I agree that a good idea may be to purchase the manual. I've been using the exploded diagrams from CrowleyMarine.com which are excellent, but agree that they don't tell you step-by-step how to remove and replace parts.

Is this one of any help in the future by chance?
http://www.hedges-uk.com/boat/Merc/o...nd%20Above.pdf

Dated Dec 1997 it covers my 2000-01 90hp, so it should cover yours too.