Replace Lower Crank Seal on 1957 Johnson 35HP?

[nj-boatbuilder57]

Wonderful & timely thread. When I built my (same) engine from parts, one of the things I didn’t do was a complete removal of the powerhead from the exhaust tube. This might be a good thing to do over the winter.

I’d appreciate any more photos you can post showing the disassembly & reassembly.

[bobw]

Here’s a series of sequential photos I took when replacing the lower seal on one of my motors. The c-clip, carbon seal, spring and washers were all in good shape but I did install a new O-ring inside the carbon seal. No problem to remove or replace, just need to handle the carbon seal very carefully and need to hold downward pressure on the spring when removing and installing so it doesn’t go flying across the shop.

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Attachments:

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[nj-boatbuilder57]

Outstanding! That makes things so much clearer!

What engine is that? Is my Golden Javelin similar? Exactly the same? Or totally different?

[bobw]

This is my 1972 Evinrude 25hp. Yours should be identical – I looked up your part numbers on Marine Engine and they are same numbers as mine.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[nj-boatbuilder57]

Just so I’m clear: in the parts diagram in the initial posting, I’m replacing #13 and #14. For the remaining parts 15, 16, 17 & 18, I’m re-using what’s already in the engine (unless I find something broken). And for #13, a "square ring" is preferred over an "O" ring. Correct?

[frankr]

They changed to the quad ring about 1959-ish. Reason is, the shaft can move up and down a bit within the bearings. As it does so, the carbon needs to slide on the shaft to maintain contact with the lower bearing. The quad ring is better suited to sliding than an o-ring because the o-ring tends to roll rather than slide.

No need to replace the carbon unless it is broken (or one of the very early ones without the raised sealing surface). Just replace the o-ring / quad ring.

[The red boat]

so if i am replacing the crummy lip seals in my 1955 Johnson RD-17 with the carbon seal assembly, is there a source where I can get all the parts i need like the washers, spring, retainer clip, etc.? or do i need to find sources for all the pieces individually?

Looking at parts diagrams, it seems like the swap to carbon seals requires all those parts that are currently not on the crankshaft.

[frankr]

You must also change the lower main bearing.

[bobw]

As Frank noted, you will also have to change the lower crank bearing for this swap. You can find all of these parts at Marineengine.com or search on Ebay for NOS or used parts. You should probably try to find a new crank bearing but a used carbon seal, spring, washers, retaining clip should be OK, but install a new quad ring in the carbon seal.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1957 Evinrude Fastwin 18
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[olcah]

Yes, to change the seal on the crankshaft lower bearing from a lip seal to the carbon seal you must change the lower crankshaft bearing. To change that bearing you are going to have to open the crankcase halves. Then you will also be able to change the oring that goes around the lower bearing outer diameter. Look also on Ebay for the parts. Sometimes you can get a deal especially for the lower crankshaft bearing which is expensive.

While the crankcase is open it is easy to install a new lip seal on the top crankshaft bearing. I would do that too for sure. Notice that there is NO oring around the top crankshaft bearing. If you put one in it will block the top bearing drain.

Here is a photo of a 1956 Javelin that might help. Notice the oring around the lower crankshaft bearing and that the upper crankshaft bearing does not have an oring. The dark band at the upper end of the upper crankshaft bearing is the lip seal. It slips onto a step at the end of the bearing. It is easy to drive the seal off and then press a new one on.

• This reply was modified 3 years, 5 months ago by olcah.

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