Re: Replace Lower Crank Seal on 1957 Johnson 35HP?

[olcah]

I just completed a similar job on a 1956 Johnson 30 HP. I believe the parts for 1957 are the same as for 1956. You have a carbon lower seal (good). #12 oring goes around the outside of the bearing. The only way to replace it is to open the crankcase halves. Since it is stationary (and probably sealed by congealed oil/gas anyway) I would not replace it. The carbon ring, #14 when new has a portion of the top surface raised up. That surface touches against to smooth bottom of bearing #11 and makes a seal. As the carbon wears that surface is worn down so you should replace depending on wear. The carbon is very brittle and thin wall. Don’t be surprised if you break it removing/installing it. You can find the carbon available NOS on fleabay/other suppliers at much lower price. You really need to replace #13 oring. It fits in the inner groove of the carbon. It too is available from others. For #13 experienced people recommend instead of using the 302540 oring with round cross section, that an oring with a square cross section #305098 be used. I have done that on a several seals but on one motor found that the square ring fitted too tight to get the carbon onto the crankshaft so used the oring on that one. The square ring is supposed to be able so slide without rolling as the crankshaft moves up and down.

When you remove the circlip notice which side is outward. I think you want the rounded edges to face outward but am not sure. Maybe others more experienced can shed some light on that.
Hope this helps.