Lower seal

Charlie61 · Aug 22, 2012

Sorry but I have read and have service manual but can not understand how to install lower unit seal when I remove the old seals the inner seal was going the same way as the outter seal . I saying that the lips that gose around the shaft are faceing the same way. in the manual one going one way and the other going the other way.
I think the inner lip could go to the prop, and the outter lip to the inner gears?
please help I have also watched you tube change out but it is not helpful.
I have a picture a with lips going inner to prop and outter to gear box "A" and "B" inner going to gear box and outter going to prop.
which is right? thanks

Texasmark · Aug 22, 2012

Re: Lower seal

I have a 90 hp serv manual in front of me. It shows the outer seal faces out...rubber outside, metal inside, and the inner seal just the opposite....rubber toward inside of engine, metal toward the prop. In this configuration, the spring tension of the rubber seal is improved by any pressure from water or LU oil.

HTH,

Mark

minuteman62-64 · Aug 22, 2012

Re: Lower seal

Year & HP of motor? My '82 Mariner 30 HP service manual shows the seals on both the prop shaft and drive shaft both facing out (rubber to the outside). I am speculating that the designers figured it was more important to keep water out than lube in.

Charlie61 · Aug 22, 2012

Re: Lower seal

the inner seal is rubber and the lip could go looking at prop or looking at gears?
outter seal lip go looking at gear box or looking at prop?
I'm sorry it's not getting to me! I've put new starter,triper, switch box rebuild the carbs but I can not get this in my head right!
I belive" A" is the right way the inner lips to the seals are faceing each other

minuteman62-64 · Aug 22, 2012

Re: Lower seal

I didn't describe the manual diagram very clearly. My manual shows all of the seals installed so that the maximum sealing effect is to the outside of the gearbox (so they do more to prevent water getting in than they do to prevent lube from leaking out).

At the risk of violating all sorts of copyright laws, here's what my (1982, 30 HP Mariner) manual shows.

Charlie61 · Aug 22, 2012

Re: Lower seal

minuteman62-64 said:
I didn't describe the manual diagram very clearly. My manual shows all of the seals installed so that the maximum sealing effect is to the outside of the gearbox (so they do more to prevent water getting in than they do to prevent lube from leaking out).

At the risk of violating all sorts of copyright laws, here's what my (1982, 30 HP Mariner) manual shows.

thank you so most that what I been wanting to see! what and who's manual do you have I am going to check mine again/thank's again

Charlie61 · Aug 22, 2012

Re: Lower seal

hope you look at this again minuterman shows inner lips going the same way , in my manual the inner lips go away from each other in post 5 I posted pictures of the seal hope you can see the lips on inner seals the black rubber one is the inner seal but I still not understanding which way the lip going ?
this is for texasman

SilverSS07 · Aug 22, 2012

Re: Lower seal

My Seloc manual shows the outer seal facing the prop and the inner seal facing the lower unit- like texasmark said. What engine are you working on? Obviously some are different.

minuteman62-64 · Aug 22, 2012

Re: Lower seal

Charlie61 said:
thank you so most that what I been wanting to see! what and who's manual do you have I am going to check mine again/thank's again

That is from the factory service manual for my 1982 30 HP Mariner. If you go to the Crowley Marine site, and search for parts, you can dial in the exact motor you have and get the parts diagrams that are in the factory manuals.

Again, it seems that the answer depends on the year/model of motor you have.

Charlie61 · Aug 23, 2012

Re: Lower seal

SilverSS07 said:
My Seloc manual shows the outer seal facing the prop and the inner seal facing the lower unit- like texasmark said. What engine are you working on? Obviously some are different.

It's a 1983 1115hp inline 6cyc mer

carholme · Aug 23, 2012

Re: Lower seal

Lip of inner seal (58) should face in and
lip of outer seal (58) should face propeller

From here, page 316:

http://web.ebscohost.com/serrc/pdf?...d-b931-a5ed3305ba47@sessionmgr10&vid=4&hid=17

Though one faces in to hold the oil in (inner) and one out (outer) to keep the water out, you will find many with both facing one way or the other, which appears to be personal preference. For example, when you see both facing in, it is sometimes a method to pass a pressure test, whereas with lips facing out, it is easier for the air pressure to lift the lips if the sealing surface is worn and fail the pressure test. Some feel that there is no water pressure acting from the outside, so why not ensure that oil does not get out.

If the sealing surfaces of your prop shaft are in good condition, outer out and inner in is the norm.

Gerry

Texasmark · Aug 23, 2012

Re: Lower seal

One reason for the inner seal facing in is that the gearcase is sealed. Even though when filling there is a slight unavoidable air gap, it could still build up pressure. Additionally, the gears in there are rotating at high speed (2500 rpm for a 2:1 gearbox at engine rpms of 5000). Any pressure from the outside would be slight as there is no mechanism to cause it to be much of anything. Water pressure is 1/2 psi per vertical ft. Running in F gear actually has a vacuuming effect mitigated by exhaust gasses. Possibly R could put some pressure on it but the prop is in the way.

For me, common sense prevails and I agree with my manual. Additionally, as I recall, these seals come with a spring around them which helps them to stay put even when worn.

My 2c,
Mark

Charlie61 · Aug 23, 2012

Re: Lower seal

thanks Carholme and Texasmark. I'm going to do it like you say , to me it is common sense but I try to go by the book . I just could not get it I did go to ebscohost and my manual it not the same .
I feel safe doing outer out and inner in .
Thank's for all you'll help!!!!!!!!!!!!!!

minuteman62-64 · Aug 23, 2012

Re: Lower seal

Charlie61 said:
It's a 1983 1115hp inline 6cyc mer

Damn, that's one BA motor

Glad you got it resolved.

Lower seal

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