Correctly installing upper and lower oil seals on a 1998 Yamaha C115TLRW

[99yam40]

I have no idea what

the rubber cupped almost hexagon looking gasket

you are talking about.
pic or part number might help.

are you sure it is lower gear lube that you are seeing?
did you smell it?
lower gear lube stinks like no other oil

[TownsendsFJR1300]

The link to your LU:
https://www.boats.net/catalog/yamaha...rive-1-115-130


There's a damper seal (part #9) that can cause issues if damaged/,missing: https://www.boats.net/catalog/yamaha/outboard-by-year/1998/s115tlrw/lower-casing-drive-2-115-130


Which part are you referring to, the hexagon looking gasket? :



Capture.JPG

[Soundear]

Thanks for the response guys...... I've been checking my post for a response and did not see any at the location I posted at - maybe because it was a continuation of my April post! Only after going to my message center did I see there was a response, so I clicked on your name and saw both responses


Damper Seal:

Truthfully, I only went as deep as replacing the thrust Bearing (#34/35), seals above that and water pump w/ Gaskets & impeller. The part you're speaking of (the damper seal) is one I've not replaced. Do you recommend I do?

Odd Hexagon Like Gasket:

Well, geometry was never a strong suit for me.....
The Gasket that was missing is the Muffler Gasket - #29





And yes.... that gear lube does have a foul smell that's unmistakeable!!

[TownsendsFJR1300]

Re the dampner. If it's there and in good shape, no reason to change it.

That exhaust gasket, obviously it should be there.
Will exhaust pressure, (just thinking out loud), from the engine, with no gasket there, pressurize the LU and cause the seals to fail?

Dunno, but suspect it's very possible.

Pressure test as you know is a very low PSI for a very short period of time
Exhaust pressures (I would think), would be MUCH higher and prolonged (if indeed it's pressurizing the LU blowing out seal(s). )

Needless to say, replace that gasket and look closely for any other parts missing / damaged...


.

[Soundear]

Update......
I finally found my main problem! Last year, I had to remove the lower unit bearing housing to change the o ring & seals. It took me days using a Map torch until finally it broke free. Apparently, when I re-installed it, I didn't put enough torque on the castle nut. I discovered it only after the second seal change when I pressure tested it to see air coming from behind the seals! I tightened down on that castle; reinstalled my upper and lower seals and have been dry ever since. Again, thanks to all who had suggestions on my fix.

[Keithbaja]

Clean up the with crocus cloth. Then dap "Triple guard or spline greez between seal and use alot. Also smear over the SS seal spring for a good Job..

[Soundear]

Thanks Keith!
I did that exactly! I used Yamalube.... is that as good as Triple Guard or Spline Greez?

[Keithbaja]

I myself love triple guard. The reason for packing the spring side is help keep the ss springs from falling out when installing seal's. Also pack between seal's so they don't start off dry & keeps them lubed. The bearing carrier needs to in 1 way only. There is a oil hole/passage the needs to be aligned. You can triple guard on drive splines but NOT the top of drive shaft. Small mention. The two upper seal don't get bottomed out.. common mistake. The top seal should be sighty bellow ridge of carrier. Also remember while the lwr is sitting around with water in it can do some really bad damage. I sem to be the only tech around here that uses "spline grease.. u might post some clear pics of driveshaft area bellow w/p to look at the 2 wear rings on it. Also when in stalling locking collar. U must be pulling up and turning clock wise. Oops,, I let the secret out !!LOL

[Soundear]

Wow! That’s some really good information that I really appreciate! ......just for clarity:
*TripleGuard is your preference
*I did pack the new seals both with Yamalube
*I do believe I put the 2 upper seals in with the first “bottomed out” the second, I installed until It bottomed out to first seal
*I assembled the lower Unit on my motor and have run it now for about 20 hours. I think I solved my leak issue by cranking down on the castle nut holding the carrier at the prop shaft in. I discovered the carrier leaking from behind the seals at the O ring when I air tested it and saw oil oozing from behind the carrier. I reinstalled the 2 lower seals (packed) and all appears to be dry as a bone after I inspect it for oil leaks after a trip! Because I’ve had not very good luck previously, I’m ignoring the fact that I should check the LU oil at the fill screw for water intrusion.
*Im still a bit in the dark on “Spline Grease” and it’s advantages over other marine grease.
*You mentioned what sounds like an important tip to implement when installing the “locking collar” excuse my ignorance but could you explain which collar you’re referencing?
I wish I had taken photos but didn’t and you referenced “wear rings” on the driveshaft area below the “W/P”. By trade, I’m an audio engineer, my hobby is working on my boat and motor when I need to. I guess I fall into the “weekend warrior” category, so again excuse my ignorance on what a W/P is and where I can locate those wear rings

[99yam40]

Wow! That’s some really good information that I really appreciate! ......just for clarity:
*TripleGuard is your preference
*I did pack the new seals both with Yamalube
*I do believe I put the 2 upper seals in with the first “bottomed out” the second, I installed until It bottomed out to first seal
*I assembled the lower Unit on my motor and have run it now for about 20 hours. I think I solved my leak issue by cranking down on the castle nut holding the carrier at the prop shaft in. I discovered the carrier leaking from behind the seals at the O ring when I air tested it and saw oil oozing from behind the carrier. I reinstalled the 2 lower seals (packed) and all appears to be dry as a bone after I inspect it for oil leaks after a trip! Because I’ve had not very good luck previously, I’m ignoring the fact that I should check the LU oil at the fill screw for water intrusion.
*Im still a bit in the dark on “Spline Grease” and it’s advantages over other marine grease.
*You mentioned what sounds like an important tip to implement when installing the “locking collar” excuse my ignorance but could you explain which collar you’re referencing?
I wish I had taken photos but didn’t and you referenced “wear rings” on the driveshaft area below the “W/P”. By trade, I’m an audio engineer, my hobby is working on my boat and motor when I need to. I guess I fall into the “weekend warrior” category, so again excuse my ignorance on what a W/P is and where I can locate those wear rings

I would think wear rings on a shaft would be the areas the seals ride on the shaft

[TownsendsFJR1300]

Wow! That’s some really good information that I really appreciate! ......just for clarity:
*TripleGuard is your preference
*I did pack the new seals both with Yamalube
*I do believe I put the 2 upper seals in with the first “bottomed out”" the second, I installed until It bottomed out to first seal"

I believe that UPPER SEAL should NOT BE BOTTOMED OUT... But a space in-between them..


*I assembled the lower Unit on my motor and have run it now for about 20 hours. I think I solved my leak issue by cranking down on the castle nut holding the carrier at the prop shaft in. I discovered the carrier leaking from behind the seals at the O ring when I air tested it and saw oil oozing from behind the carrier. I reinstalled the 2 lower seals (packed) and all appears to be dry as a bone after I inspect it for oil leaks after a trip! Because I’ve had not very good luck previously, I’m ignoring the fact that I should check the LU oil at the fill screw for water intrusion.
*Im still a bit in the dark on “Spline Grease” and it’s advantages over other marine grease.

*You mentioned what sounds like an important tip to implement when installing the “locking collar” excuse my ignorance but could you explain which collar you’re referencing? He's referring to the collar just above the WP impeller. You should pull the driveshaft UP, rotate the drive shaft slowly while tapping that collar down. This prevents knocking when at slow speeds

I wish I had taken photos but didn’t and you referenced “wear rings” on the driveshaft area below the “W/P”. By trade, I’m an audio engineer, my hobby is working on my boat and motor when I need to. I guess I fall into the “weekend warrior” category, so again excuse my ignorance on what a W/P is and where I can locate those wear rings

See above bolded

[Soundear]

Well, it's been holding up. Hopefully I won't experience water intrusion - but if I do, I will certainly follow both of your suggestions.... Thanks again!