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Mating Lower Unit question

M

Markfla

New member
Hello, first post. I am reinstalling the lower unit on my 1985 Evinrude 55 Commercial. My factory manual specifies sealing the lower unit mounting flange to the mid section. There were remnants from sealer when I removed it.

I don’t have a problem with using sealer, but is it necessary? The housing of the lower unit fills with water by design. It’s two machined surfaces. Here is my question. Is it necessary to apply sealer to the mounting face of the lower unit? Thank you.
 
Well, this is interesting. Most people post the question as concern over leakage from that seam. That is why it is supposed to be sealed. Your Insite is correct, the leakage is not a problem. Anything coming out of that seam was headed back to the sea anyways.
 
Sealer will help "cushion" the seam and protect the finish. The paint is applied for a reason to discourage corrosion/oxidation. Not a real concern for most freshwater applications, but saltwater? Yes! Motors that sit in water all summer, like on a pontoon boat are another consideration.
 
Salt water mostly. Flange surfaces look good. All good points. No harm in using sealer again. I have to confess I got watching you tube videos and noticed the techs were just installing the lower unit without sealer. Thought it was unlikely the manual would specify sealer if they didn’t think it was needed. I’m on the side of protecting the mounting surfaces. Thank you.
 
I think its a wise choice. Operating conditions kinda dictate how I decide too. This case its not about sealing, as Gator stated, but about protection.
 
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