72 johnson 20 hp lower unit, ds and ps seal questions

[dkonrai]

72 johnson 25 hp, tiller short shaft.

rebuilding the lower unit and i have a manual. the old ds and ps seals are one piece and the replacement is a two piece.
ordered a sierra 18 2684. do i just install one seal on for the drive shaft and propshaft? if i double the seals on the ds, it seems like it will be a little tall in profile. which way do i set the seals, i assume the flat side towards the gear, and the upper would be flat side up (facing the tower).

would it be ok to use one seal vs two?

do i use gasket seal on the main bearing carrier? it looks like the old was sealed.

the good is the gear and lutch dog look almost new so glad that there was not a whole lot of wear.

manual calls to use a silicone to seal the spaghetti seal, ok to use regular 100 % waterproof silicone?

sorry for so many questions but this is the first of four that i will be rebuilding and dont want to mess up. waiting for parts isnt my favorite pastime, because i screwed up and had to order replacements:facepalm:

dino

 

[dkonrai]

Re: 72 johnson 20 hp lower unit, ds and ps seal questions

here is the gear set

 

[F_R]

Re: 72 johnson 20 hp lower unit, ds and ps seal questions

In many cases, two thin seals are provided instead of one thick one. Both are to be installed if there is enough room. Otherwise, just use one installed same side up as the original. Where two are used, one goes lip down to keep oil in and the other goes lip up to keep water out. Newer motors use the two seals, reason the kits provide them.

Yeah, I know, these pictures are not of your motor. But seal orientation still applies

 

[Howard Sterndrive]

Re: 72 johnson 20 hp lower unit, ds and ps seal questions

do i use gasket seal on the main bearing carrier? it looks like the old was sealed.

manual calls to use a silicone to seal the spaghetti seal, ok to use regular 100 % waterproof silicone?

I haven't put sealant on the bearing carrier, but hey, it wouldn't hurt to back up the o ring.

I use automotive RTV for the spaghetti seal . I like the Permatex copper.

The last 20 I did is leaking again. The propshaft was quite worn where the seal lips ride. I installed a speedi sleeve, but either I missed and have the seal riding the edge of it, or something else going on. I have to take that one apart again in the spring. I might see if anyone locally does spray welding to repair the shaft.

 

[dkonrai]

Re: 72 johnson 20 hp lower unit, ds and ps seal questions

In many cases, two thin seals are provided instead of one thick one. Both are to be installed if there is enough room. Otherwise, just use one installed same side up as the original. Where two are used, one goes lip down to keep oil in and the other goes lip up to keep water out. Newer motors use the two seals, reason the kits provide them.

Yeah, I know, these pictures are not of your motor. But seal orientation still applies

fr,
the drive shaft seal, it appears to go face to face? so the top seal will be inverted?? or does it really matter? the prop seal looks to be installed the way i thought, cup to cup with the seal facing out towards the outside/gear set.

thanks for the quick reply.

howard,
re: the carrige assembly seems to have sealant on the bearing and carrier that is why i asked. no reference on the service manual.

dino