2 seals in the retainer, but only 1 in the kit....

[Gas Giant]

Engine is a '61 Evinrude Lark III, 40hp, model# 35524. The lower unit seal kit is Sierra 18-2686.

Okay, short story long, I am in the process of re-sealing the lower unit on my motor since I got a bunch of water out when I drained it. I picked up a seal kit, Sierra P/N 18-2686 thanks to this forum. However, I did a search and didn't quite find the answer to this question. (Or I did a bad search, we will see )

Everything was going well, (thanks to my PDF manual and iBoats posts!) but on the prop shaft there is a seal retainer, and it has 2 seemingly identical seals installed in it, back to back, sort of like this ][. However, my seal kit only came with one of those seals, and looking at pictures of the contents of the kit online I don't think it comes with the 2nd one. (At first I thought maybe a factory worker somewhere let kit one slip through the cracks with only one seal). My manual doesn't mention a 2nd seal, and the parts breakdown on marineengine.com only shows the one seal with a quantity of 1 - no 2nd seal.

So, I am calling upon the infinite wisdom on this site for advice. Is it only necessary to replace one seal? Both of the seals in the retainer look decent, and are still pliable (not hard and cracked like the transmission tailshaft seal on my Bel Air was :redface.

If so, which of the two seals should I replace? The one towards the propeller or the one towards the gears?

And, any helpful hints on removing one seal without harming the other?

Thanks guys!

For reference, here is the retainer and new seal in a bad photo I took:

 

[Joe Reeves]

Re: 2 seals in the retainer, but only 1 in the kit....

On the 40hp model, as well as many other models incorporate that aluminum propshaft seal housing, part # 303050. It houses but one seal, part # 302564. It is installed so that the edge and spring portion of the seal faces the gears... [ gears ... preventing the lube from leaking out.

Make sure that you have the proper 302564 seal. The part number is usually right on the seal itself.

 

[F_R]

Re: 2 seals in the retainer, but only 1 in the kit....

True, the original setup was one seal. However, 303050 seal housing is replaced by 397186, which has two seals, back to back, so somebody has already replaced it. May I mention that 397186 costs $106.64? It certainly would be a shame to trash it if the seals are still good (!!).

 

[Gas Giant]

Re: 2 seals in the retainer, but only 1 in the kit....

Yikes!!!! I suppose its best to leave well enough alone and leave those seals in there!

I assume then that there isn't a way to remove those seals from the housing, and you have to replace the entire housing?

 

[Joe Reeves]

Re: 2 seals in the retainer, but only 1 in the kit....

Apparently I retired before that expensive "improvement" came into being. I think I'd revert to the older setup myself. The older seal is still available and the 303050 housing should be readily available in the outboatd junk yards.

 

[F_R]

Re: 2 seals in the retainer, but only 1 in the kit....

Now I'm starting to get into unknown territory. Sierra sez their part number 18-2021 is 1/4" thick. Replaces OMC 302564. Will two of them fit into 303050??? I dunno.

BTW, the single seal is best at keeping oil in, but not the greatest for keeping water out. Back to back seals keep oil in AND water out. That's why the change.

 

[Gas Giant]

Re: 2 seals in the retainer, but only 1 in the kit....

When I get home I'll take some measurements on the 303050 to see if its at least 1/2" thick.

But, since the seals in the housing appear to be in good shape, I think I'll take my chances and leave them in there.

 

[Joe Reeves]

Re: 2 seals in the retainer, but only 1 in the kit....

Hmmm... 302564 is the original PS seal that was used from day 1 on the 303050 housing. Unlikely one could fit two of them in there. Is it possible that they take lessons in how to confuse people?

 

[Gas Giant]

Re: 2 seals in the retainer, but only 1 in the kit....

The housing measures 0.57" thick, so two 0.25" seals back to back will fit with a 0.07" gap between them, which is what appears to be the case.

Joe, I don't know if they take lessons on how to confuse people, but I am fairly confident they GIVE them!

 

[lindy46]

Re: 2 seals in the retainer, but only 1 in the kit....

Did you pressure test the gearcase to see which seal/s is/are leaking? Prop shaft seal may not be the leaky one.

 

[Gas Giant]

Re: 2 seals in the retainer, but only 1 in the kit....

lindy46, no, I didn't....hindsight is 20/20!

Actually, I haven't found any seals that were obviously bad, so I am not sure how all that water got in there.

 

[Tim Frank]

Re: 2 seals in the retainer, but only 1 in the kit....

Have you always faithfully changed out the seals on the drain plugs?
That may be the single most common source of leakage.

 

[F_R]

Re: 2 seals in the retainer, but only 1 in the kit....

Shift rod seal?? Grooved shaft (s)?? Sloppy installation of the spagetti seal by the last guy that had it apart?? Drain/fill plug washers?? Skeg screws not tight?? (sock them in there hard).

 

[1946Zephyr]

Re: 2 seals in the retainer, but only 1 in the kit....

Apparently I retired before that expensive "improvement" came into being. I think I'd revert to the older setup myself. The older seal is still available and the 303050 housing should be readily available in the outboatd junk yards.

I just got the old 303050 in the mail today from Sea-Way Marine.

 

[Gas Giant]

Re: 2 seals in the retainer, but only 1 in the kit....

Tim - I haven't had the engine for very long, and the only history I had on it was that it hadn't been run in a long time. However, since two new seals came with the kit, new drain plug seals will be going in!

F_R - I didn't see any grooved shafts, and the shift rod seal didn't look bad when I got it out. (New one went in anyway) Not sure about the spaghetti seal, I'll have to take a 2nd look, and the screws on the skeg.....well they unnervingly easy to remove...... I haven''t tried putting the new spaghetti seal in yet as I forgot to get the sealing compound on my way home yesterday.

I'm actually surprised at the condition of the gears, bearings, and other components in this LU...with the amount of water that came out, I was expecting the gears to be trashed, but everything in there looks great.

 

[1946Zephyr]

Re: 2 seals in the retainer, but only 1 in the kit....

1961 Lark III? You expected the gears to be trashed? HAH This is when they built good outboards. Oddly enough, you'll find good metal inside, but bad seals and oil. I have no idea why. LMAO You got lucky. Fix 'er up nice and you'll have a good runner. Funny is, I bought a re-seal kit and it has three identical seals that I won't use in the lower unit I have. Why did they do that??

 

[Willyclay]

Re: 2 seals in the retainer, but only 1 in the kit....

I just got the old 303050 in the mail today from Sea-Way Marine.

Will you share how much you paid?

 

[lindy46]

Re: 2 seals in the retainer, but only 1 in the kit....

Not sure about the spaghetti seal, I'll have to take a 2nd look, and the screws on the skeg.....well they unnervingly easy to remove......

If those skeg screws came loose without an impact driver, they were most likely too loose. When you put it back together, use an impact driver to tighten them.