Johnson 40 crank seals

[gullake]

I'm replacing upper and lower crank seals on my "61 Johnson 40HP. Upper seal is in finished and went well. I have the lower seal assembly out and have some questions. The quad ring goes inside of the groove in the retainer but it is narrower than the groove and has some side to side play. The old one I took out fit tightly but the rubber quad ring may have swelled over time. My Seloc manual stated that the side of the retainer with the raised edge goes up. The old one came out with raised side down. May have been previously replaced and done wrong, I don't know. Also my parts catalog shows an o-ring going next to the seal retainer. No o-ring was there when I disassembled. The o-ring with my new parts doesn't seem to fit anywhere. Not sure what to do here. I ordered parts by part # from factory catalog and numbers matched the packages I received. This whole seal assembly seems sort of goofy to me and I can't picture how it can do much sealing. I realize this is not a common repair but if anyone has been there before or has any insight/opinions I'd like to hear them.
Thanks, gullake

 

[F_R]

Re: Johnson 40 crank seals

I'm replacing upper and lower crank seals on my "61 Johnson 40HP. Upper seal is in finished and went well. I have the lower seal assembly out and have some questions. The quad ring goes inside of the groove in the retainer but it is narrower than the groove and has some side to side play. The old one I took out fit tightly but the rubber quad ring may have swelled over time. My Seloc manual stated that the side of the retainer with the raised edge goes up. The old one came out with raised side down. May have been previously replaced and done wrong, I don't know. Also my parts catalog shows an o-ring going next to the seal retainer. No o-ring was there when I disassembled. The o-ring with my new parts doesn't seem to fit anywhere. Not sure what to do here. I ordered parts by part # from factory catalog and numbers matched the packages I received. This whole seal assembly seems sort of goofy to me and I can't picture how it can do much sealing. I realize this is not a common repair but if anyone has been there before or has any insight/opinions I'd like to hear them.
Thanks, gullake

What's goofy about it? It is a very common seal design, used on water pumps long before it ever appeared on outboards. It is a very effective seal, if installed correctly.

Anyhoo, the quad ring goes inside the carbon seal--the part you are calling a retainer. Never mind the fit, it isn't supposed to be a jam fit, width-wise.


The o-ring you are looking at goes around the outside of the bearing and you can't see it without tearing the powerhead apart. So, forget about that part.

Ok, here is how it stacks up: Smear some grease on the quad ring, and push the carbon seal onto the shaft--raised edge up against the bearing!!! Then the large spring retainer, cup side down. Then the spring. Then the small spring retainer, raised side up--fits inside the spring. Then the snap ring, flat side down. Note the flat side is the side with sharp edges.

How it works: The quad ring seals the carbon seal to the shaft. The raised side on the carbon seal rides on the ground flat end of the bearing, sealing it to the bearing. So, the carbon is the go-between from shaft to bearing.

 

[gullake]

Re: Johnson 40 crank seals

Thanks to F R, you know your stuff. Maybe I'm what's goofy. I've been installing seals in all sorts of stuff for 40 years but never saw anything like this. With your help it now makes sense. I couldn't see how it would seal around the perimeter but didn't realize it was a carbon surface, The old one was definitely upside down so no wonder it wasn't sealing. I'm trying to keep this old girl running smooth. It's a perfect fit for my vintage 13' Whaler plus it's paid for. Thanks again for the education.