Lower Unit Seals. ...leaker!!

[Shannonigans]

. . .. .. .okay. ....let me start with a poor excuse for procrastinating maintenance.. .. . ..the weather! By the time I pulled the boat last year and finished with the refuel at work it was way to cold to think about my poor baby. . .....and with the late spring weather. .....well it took me until this past weekend to drain the lower unit oil. . ......yes. I know. . ....dumb.... ...and the results sucked! There was a noticeably small amount of water in it. ......about half of the oil came out discolored. It was a light green.. ..not the frothy looking tan crud that comes from a bad leak, but (I believe). .....a leak none the less. Annnnnd. ...with my mechanic going on vacation for 10 days and me being cheap. ......the skills will be put to the test.

. . .......with a quick scan of the manual and of course some YouTube. . ...I was on my way to seeing if I could find the leak. I got a hand pump from work and rigged it up to the fitting for my oil fill hand pump. . . ...slowly put 10 pounds of air in it and some snoop (soap water). . .....and in less than a minute the ugly bubbles appeared. Luckily for me it was the shaft seals and NOT the prop shaft seals. Not too sure I would have the patience to mess with those.

. . . ..here's a few pics of the set up and the leak. I hope to post more pictures of the removal/install when I change them.


. ....here is the set up....hand pump, pressure gauge, and the leak...........



............just a close up of the gauge and the leaker........pretty easy to see with all those bubbles!!



.................this is the prop shaft seal(s). . ....thankfully bubble free for about the 30 minutes I left it.




. .. .. .......like I said. . ....will get some more pics of the actual removal/install in a week or so. Hopefully it may help some one that's questioning sending it to the shop or try it themselves. . .......because if you're as 'frugal' as me. ......you'll try it. What the heck. . ....it's broke anyway....right?!!

 

[TomS]

I just replaced both prop and drive shaft seals this weekend - had picked up some fishing line around the prop at the end of last season and had milky oil last fall when changing it out.

I didn't have the equipment to run the pressure test first, so assumed the prop shaft seals were the main culprit, but wanted to do the drive shaft seals as well as I had read they were the easier of the two.

I'm sure we watched the same 3-part video on Youtube.. but for me, once the three bolts on the drive shaft housing were removed I had to use a hammer/screwdriver to rotate the housing left/right a few times before it loosened up enough that I could pry it up with two screwdrivers.

I didn't want to mess with the needle bearing and risk damaging it (I wasn't 100% sure which way it should come out of the shaft housing) so I used one of those three prong bearing pullers to slowly work out the two oil seals. It was tough getting the arms of the bearing puller to "bite" into the seals while trying to keep them away from the needle bearing, but they slowly got to the point where they created enough space between the two that I could punch out the seals from the opposite side.

I used a section of PVC pipe to seat them back into place.

For the prop shaft seals, I ended up drilling two holes, then threading a couple of screws into each seal and using two sets of pliers as leverage to pull them off. I was worried about damaging the prop shaft itself, so used a pin vise to drill the holes (took forever) by hand. Same thing as before, used a section of slightly larger PVC to re-seat the seals.

I had such good momentum going after getting those two projects completed without any gotchas that I decided to keep working my way down the to-do list. I checked the poppit valve and both thermostats to make sure they were clear - and of course snapped off a bolt when re-installing the t-stat covers. I ended up having to remove the cylinder head cover in order to get the bolt out, so now I am waiting on a replacement bolt and gasket before I can clean everything up and get it back together.

One step forward and two steps back...

-- Tom

 

[Shannonigans]

One step forward and two steps back...

. .. . . ...yup! Seems to be my theme this year, but. . . . ....at least I'm learning as I go. I did the t-stats, popet valve, impeller last year. When I am done with the seals I want to try and find the engine 'cough' I have at idle. . . ...should be interesting which two steps back I will take during that!!

. . .....as far as the seals. . . ..yup. . .same 3 part video!! I will be doing the same thing you did. . ...minus the prop shaft seals. One question I have... that may be apparent once I remove the seals. . ...is how do I know when they are in enough? Is there a lip they will hit? It may have been in one of the 3 videos, but my ADD kicked in and I think I started dreaming about summer and fishing..............

 

[TomS]

Yes, I believe there is a lip as there was a noticeable "thunk" when they were fully seated.

-- Tom

 

[Megabyte]

When I am done with the seals I want to try and find the engine 'cough' I have at idle.

I reported that 'cough' when cold in my 225 OX66 to my mechanic last year and I'm pretty sure it was resolved when he replaced the 3 low pressure fuel pumps.

I need to go back through my notes as he did a 'major' service last year.
Plugs, t-stats, poppit, low pressure fuel pumps, all fuel filters (including the VST ), complete water pump kit, lower unit oil... the works.

 

[Shannonigans]

I reported that 'cough' when cold in my 225 OX66 to my mechanic last year and I'm pretty sure it was resolved when he replaced the 3 low pressure fuel pumps.

. . ....thanks...they are one of the first things on the list to look at (suggested by my mechanic) . ......sad thing is I just replaced them a couple years ago. ....mechanic said with the crap fuel and quality of parts that he's had to replace them after one year on some peoples boats. .....

. . ....I'm sure I'll find it. ...just a slow list of things to check/work through!

 

[Shannonigans]

. . .....so today was the day. ...removing and replacing the seals. Ran down to Boat's Inc to fill a bag full of goodies. ....and while I was there asked one of the techs if they install the seals dry or lube them (we install a lot of seals at work dry). .. ....he said definitely use a light coat of gear lube. ....and with that info I was off.

. .. ....the assembly is pretty easy to take out. ....remove the 4 bolts and gently pry it out. I used 2 large screwdrivers ....one on each side. ....if it's being stubborn... just tap it (side to side) with a drift pin to free it up.

. ....here is a pic of it prior to removal and the bolts you will be taking out.



. . .....and a pic of it out. ....be sure to note the arrangement of the spacers so you can put them back the same way.. ...they are on the bottom side and may not come out with the assembly. Mine did not so I just used a telescoping magnet to reach in and get them out. ......



. .. .....just a shot of the inside. ....I put a rag in it after the pic just to keep out debris.





. .......I don't own a vise, so I went a little redneck and just screwed it down. It worked really well .. .... I was able to pry the upper seal out with just a screwdriver. . .....had to work it around the seal for a bit before it popped right out. ..... I also put a piece of metal under the screwdriver when I was prying, so I didn't mar/ding it.

 

[Shannonigans]

. . . .. ..for the bottom seal I flipped it over and very carefully tapped it out. Like TomS said earlir. . ....take your time. You don't want to gouge the side!! This is what I used to tap it out........




. . ........once out you'll want to clean all the crud build up off the inside before you even think about putting the new seals in. Mine was not too pretty. .. ...as you can see......also be careful not to get any crud in the needle bearings.



. . .....but she cleaned up nice. . ....all ready for the new seals.....

 

[Shannonigans]

. . . ......to get the seals in I borrowed a bearing seating tool from work. I was going to go the PVC route until I remembered we had this.. . ...made it very easy too. So. ...like the tech said. ...a light coat of 90 weight and pressed right in.. ...times two!!

. ....the seals and the tool



. . . ....and the tool in use. I basically was able to just press really hard and they went right in. A few taps with the hammer to make sure they were completely seated. .....and that was it. ...




. . . ......obviously it goes back in the opposite of how ya took it out. .. ...so I don't think pics are really needed. BUTTTT. ......be sure that you put it in facing the way it came out.. . ...you don't want to reverse it and get the oil inlet hole on the wrong side!! Also. ....there is an o-ring that you will want to inspect/replace. I couldn't find any torque specs for the bolts in the manual, so I just used 'good mechanical practices' (sorry...work term). ......

. . .. ...in all it wasn't a difficult job at all. ....just take your time and be patient. Hope it helps...........

 

[TomS]

Great post - just think how much that would have cost at a shop!

-- Tom

 

[parkerjon]

Shannonigans,

I replaced my prop shaft a couple years ago because I bent it. Replacing the prop shaft doesn't require shimming on a Yamaha OX. The most difficult thing in replacing the prop shaft seal is getting the bearing carrier out which isn't that difficult but you need a good puller and some heat. Some people do it with the prop shaft in place but I wouldn't recommended it. Replacing the prop seals is just as easy as the drive shaft seals. You did a great job documenting your repair. Wish I could be better at that but my hands always seem to be to grimy to pick up a camera.