Engine Oil leak after lower unit reinstall

Hello all, I have been reading this forum for quite some time now. Unfortunately, I am now in need of your help. I pulled a bonehead move, and need help getting out of it!!

I was servicing my twin 2007 Honda BF150 outboards. I removed the lower units to replace the water pumps. When installing the lower unit back onto the starboard outboard, I believe that I was not completely lined up and damage something in the power head.

This was my first removal/reinstall of a lower unit. I thought I had the lower unit all lined up. I pushed it on as far as I could, until there was a gap of about ½” to ¾” left. Then I decided to install and tighten the bolts to pull it up the rest of the way. During the tightening, the bolts got tough to turn, and then I heard a loud “pop”. The bolts then were easy to turn the rest of the way. I thought perhaps it was a bit out of alignment, and the pop was it slipping into the position it needed to be in (the alignment pins I thought). But now I am pretty sure it was something breaking.

I remove the lower unit and inspected it for damage, but saw none. I reinstalled it a couple more times, and everything went together fine (still had to bolt it up to get it all the way on, but no more popping sounds). About 10 minutes later (after coming back out of the garage with the port outboard lower unit), I noticed a lot of oil leaking out of the starboard engine.

It is leaking out of what I believe is the gear shift shaft seal, and down the gear shift shaft. It only leaks when the engine is tilted upward. It leaks about a drip every second, if not a bit faster. I remove the cowling, and could not see any oil in the engine bay. It is not leaking out of the oil dip stick or the oil filter, and there has not been a recent oil change that could point to residual oil from an oil change. It definitely started from my misalignment of the lower unit and the fact that I forced the lower unit into place.

So, what could I have damaged? Where can I look to confirm the damage? Can you confirm this is the gear shift shaft where it is leaking? Am I really screwed on this?? Any help would be greatly appreciated!!

Thanks for your help!!

AkBillyBow

I think you probably pushed shift shaft A up out of position. Part # 12 http://www.boats.net/parts/search/H... and Later/BF150AK0 LA/SHIFT SHAFT/parts.html

Have you tried to shift yet? If you pushed it up too far, then your shifting is going to be messed up since shift shaft A and B (part #18) would no longer be in sync.

Other than shifting being messed up, you can check by looking in the area of your first two pictures and see it the E ring and washer are still in place (parts 52 and 36) where shift shaft A goes into the undercase of the motor.

In the picture, the shift shaft from the lower unit and shift shaft A do not look like they are in a straight line with one another. It might be the parallax of the photo....only you can tell since you are there.

Also, can you feel any oil at the union in the first two pictures? I am also assuming, that since you said, you removed the gearcase and it was ok, that the oil is motor oil and not gear lube.

If you have not tried to shift and everything is am I am guessing above.....do not try to shift it. It will be easier to put it back in place with everything in sync if nothing has moved.

All that is bad enough...although it probably is fixable with some patience....however, as far as I can remember, there should not be motor oil in that area to leak out....which means, there may be an oil leak somewhere on the bottom of your powerhead. You can pull the starter and look inside the cavity for oil...although you may not see any on top of the flywheel....or maybe you will. The only way to see exactly where it is coming from, is to pull the powerhead.

I would say for now, one step at a time....get the shift shaft corrected....if that is indeed the problem.

Mike

Homdadue, thanks for your reply and suggestions. I worked on the outboard all day, and here is what I saw and learned.

You were correct about the shift shafts not lining up. I pulled the lower unit again, and learned that I had put the lower unit on with the lower unit in gear, yet the engine was in neutral. So the keyed shaft did not line up with the lower unit, and I think I pushed it upward instead of them sliding inside each other. P.S., it is really hard to tell if that is lined up, as after the upright shaft, and the water tube, and the speedo tube all get lined up, you can no longer see if the shift shaft is lined up or not. It is simply impossible to tell!!

So, the oil stopped leaking, and I am not sure why. I pulled the starter and the flywheel is bone dry. I did have the engine oil overfull, and am wondering if there is a vent tube or overflow tube that it could have came out of, layed in the bottom of the engine, and then drained out of the engine by means of the shift shaft, after I pushed the shift shaft upwards and dislodged the washer and e-ring. Does that sound possible??

With the lower unit off, the shift shaft rotates when shifted both directions. I tried to lign up the shift shaft and the lower unit gear (the key is not quite forward when in neutral). I reinstalled the lower unit, thinking I had it all right this time. Well, the shift shaft no longer rotates when I shift with the lower unit installed. So I think you may be correct that the top of the shift shaft gears are no longer lined up. The problem is they are buried inside the engine case, and I cannot see them. So I guess I need to start tearing it all apart to see if I can get to them.

Any new suggestions with the info from today? What do you think about my oil theory? Any tips to tell in the shift shaft is lined up properly when sliding the lower unit on?

Thanks again.....AkBillyBow

First....see if you can find the E ring that probably flew into the grass. There should be a washer still up there somewhere around the shift shaft ( may have dropped down).

If the long shift shaft is still inside the upper shift shaft and never came out....that is good.

Make sure that the engine shift box is in neutral.

Do the next part slowly and carefully...

Grab the long shift shaft from the bottom but putting a part of a needle nose into the bottom hole aligned with the flat spot....that way you can see much better which way the flat spot is pointing. In neutral, it should be facing toward the bow of the boat. With a gentle wiggling action push the shift rod up about 1/8" or until you can turn it without resistance to align the flat spot to the front. Then, continuing your slight wiggling, see if it will drop back down, allowing the shift shaft A and B grooves to interlock again.

DO NOT PULL DOWN ON THE LONG SHIFT SHAFT VERY HARD...it is held into the upper shift shaft with just a little ring.

Once everything is in place, you have to get the washer and E ring back in place to hold it all together.

Then you can put the lower unit on and get back to boating.

Mike

PS There are two other ways to fix this. One is the way in the manual, which is about a page long....you may get to that....and the other is to pull the powerhead and realign them (You should not have to get to that).

Thanks again for your help. I will give that a try. I did find the washer and e-ring, and put them back on the shaft before installing the lower unit. I do remember the shaft moving upward and downward a bit, so I think (and hope) all of that is in good shape. I will remove them, reinstall the lower unit like you said, and install them back on the shaft. Man that e-ring is hard to get on!! I had to buy some really long needle nose pliers to get it back on the shaft!!

Any thoughts on the oil leak, and my theory? Could it have come from an overflow vent, since I had it overfull?

Thanks again.....you have been a great help !!

AkBillyBow

My thoughts on your theory...... Maybe.

It is hard to say. You just have to keep a watch on it.

Mike

Thanks Mike. Funny that it would leak that bad, and then stop overnight without me finding/fixing anything. Also, yes there is still oil in the engine!! Running out of oil would surely stop a leak, but that is not what happened. Just thought I would add that!!

Thanks Mike!!

Hondadude, thanks for your help. I finally have everything put back together correctly, and everything appears to be working fine. My biggest issue was not getting the shift shaft into the lower unit correctly. I did not have them both in the neutral position, which also caused the teeth to tear up a bit when I forced the lower unit on. I had to file down the teeth to get everything to line up properly again.

Lessons learned: 1. Do not force the lower unit on. If it does not slide on fairly easily, something is not lined up properly. 2. Remove the e-ring and drop the washer, then pull down on the shift shaft so it extends down far enough to go onto the gear. 3. Line up the shift shaft and lower unit gear in neutral. Keep the shift shaft from pushing up when sliding the lower unit on, by holding it into place with a pair of vice grips (cramp lightly onto the shift shaft). 4. Come to this forum to look for help from others with more experience !!

Thanks Hondadude!! I could not have done it without your help!!!

AkBillyBow

I know the sick feeling in your gut when you think you will have to pull the power head to fix a "little" mistake. We have all been there.

I am glad you have it straightened out.

Thanks for the feedback. Hopefully, others will read your thread and learn before the mistake takes place.

Mike