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40hp Driveshaft oil seal Orientation

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woodduck31

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oilseal resized.jpgHey Guys, New to the fourm... I have a 40hp Mariner that I have started changing the seals in lower unit after finding water. My question is which way do the 2 new oil seals go back into the water pump plate that slides down the driveshaft? When I removed the old ones the flat side was facing up towards me.
So do the flat side face each other or Spring sides face one another?
 
Not to derail... That is interesting. I was planning to do this soon. I realize I have a different engine (60hp), but in the parts diagram for my engine, it shows the seal orientation in the diagram and it is exactly the opposite of what you describe? It shows the flat surfaces touching each other and the "spring side" to the water and the oil.

I guess it would depend on which one you consider the "first one"?
 
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snookwhaler said:
Not to derail... That is interesting. I was planning to do this soon. I realize I have a different engine (60hp), but in the parts diagram for my engine, it shows the seal orientation in the diagram and it is exactly the opposite of what you describe? It shows the flat surfaces touching each other and the "spring side" to the water and the oil.

I guess it would depend on which one you consider the "first one"?
Click to expand...
Mine is installed as you described. I was sent a pump housing base with the seals installed incorrectly. Caused a lot of lost time and effort and an additional $200.00 to keep water out of the lower unit.
 
kimcrwbr1 said:
All double seals are back to back seals. The lower one holds the oil in and the upper one holds the water out no exceptions.
Click to expand...
I stand corrected what is your serial number. I looked atthemarinerdiagrams and it shows the spring side of the seals pointing toward the water side. Contrary tologic thegearbox will not be able to hold pressure IMO. I would install them back to back the other way makes no senscto me.
 
The seals will still hold the oil in, and that's okay long as the seals also keep the water out!

You'd be surprised at how little oil is needed to lubricate a LU.

Jeff
 
To alleviate any confusion. Here is a diagram I found for my engine that shows the orientation of the seals in the housing. So, assuming all double seals get installed this way? Shows the same for the prop-shaft as well. I'm glad I ran across this thread before I did the job. Thanks for the input and to the OP for bringing this up!
 

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Here is the diagram of my motor. Based on it it shows both seals facing the same direction. I really didn't understand the diagram at first unilateral snookwhaler brought it up. I just installed mine with flat sides facing each other. I'll see what that does. IMG_0003.jpg
 
I am gonna say good call thats how they are in 99.9% of shafts with double seals. One holds for pressure and the other holds in a vacuum.
 
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