1961 Johnson 18 HP FD-15 Engine, Crank Shaft O Rings

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I'm replacing the crank on my engine. The current Parts diagram on MarineEngine.com shows only 1 O ring (Part 20) on the lower end of the crank. I have a parts diagram from an older service manual which also shows an O ring on the upper part of the shaft. My casing engine did not have an O ring installed at this location but there is a casing groove that would allow it. Should there be an upper O ring installed on the upper end or has the design been changed to rely only on the upper seal? Thanks.

 

[fdrgator]

The groove in your motor is NOT for an o-ring. Use the correct parts list for your motor.

 

[[email protected]]

Thanks for the reply. The problem I have is that I have 2 parts diagrams: 1 showing O rings at top and 1 showing O ring just at the bottom. The O ring at the bottom on my was inserted into the casing groove which I think is correct. I'm questioning whether I need an O ring at the top. I'm assuming not, but just want to be sure.

 

[fdrgator]

You stated that the diagram showing an upper o-ring was from an older service manual. There ya go....some older motors used an o-ring. Take a good look at that groove in your motor. Do you see a tiny hole drilled in the bottom of the groove? That is an oil return hole.