Crankshaft O Ring, 3 HP Johnson 1961 JW-17

[SCOTT GODFREY]

Hi there. I am rebuilding a 3 hp Johnson and there is an O ring on the crankshaft. Yet this part is not shown in any manuals. Does anyone know the part number for this or what to replace it with?

Thanks
Scott

[crosbyman]

mdl# ??

Joining AOMCI has priviledges 🙂

[Steve D]

On MarineEngine I checked your model 3 HP and all of them up to 1968 and the only year that shows an o-ring in addition to the slinger is 1966. But when I check the number for that o-ring 308117, it says it’s an invalid part number. There’s also a discussion on MarineEnginge about someone else who has a 3 HP that shows the o-ring but his is a 1968 and when you check that parts page it doesn’t show it. So maybe if you just take it to a hardware store or buy an O-ring assortment kit from Harbor Freight you might be able to match it up.

http://www.marineengine.com/boat-forum/showthread.php?458037-1968-Johnson-3hp-JHL23M-Compression-Test

[SCOTT GODFREY]

The model is a JW-17

[SCOTT GODFREY]

Thanks so much. I will continue to look a bit unless there are other suggestions and if no luck will just match up as best I can. Thanks

[billw]

That’s pretty funny. I, too, have a ’68 Evinrude 3 apart.. It has the o-ring also; and I have been down the same road. I was not really even sure if it was OEM, nor could I really figure out what it’s function even was. Nobody uses an o-ring for a crank seal like that, that I have ever seen. I can’t imagine it would last very long as an actual crank seal, when used under high rotational speed, that way. I just finished putting my power head back together with the existing o-ring. I have not run it yet; so I don’t know if that will be a mistake or not….

Long live American manufacturing!

[SCOTT GODFREY]

Thanks for the input, glad to see I am not alone. I may end up using the existing one as well.

[fleetwin]

Well, that’s a new one on me for sure… Like Bill says, an oring there seems like it would get destroyed, but I guess the oil keeps it lubed. So, I would not look for an alternative, I would just reuse the original oring as long as it looks to be in good condition…

[Mumbles]

After checking parts manuals, it seems that O ring was a one year only item, 1966, and OMC must have realised they were trying to saddle a dead horse and they didn’t use it again on the later JW or Lightwin three horse motors.

Without any forced lubrication to it, I think that O ring would get shredded or torn apart shortly after start up.

[billw]

Mine is in a ’68, even though the ’68 parts manual doesn’t show it. My o-ring is in pretty good condition, although slightly flat. I was wondering if it was some kind of additional slinger but I don’t know where it would sling anthing TO. Maybe it acts as a kind of labyrinth seal.

Long live American manufacturing!

[Author]

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