1972 Johnson 50hp 50es72c Rebuild

[JiminTexas]

Ok I am new to this and I am asking for suggestions. I am currently rebuilding this out board and reading profusely about corrosion and maintenance. Now I have nos parts and I am trying to slow (can't Prevent Corrosion totally) the process to ease maintenance in the future. I want to clean out the lower gear. What do I use to brush out the interior and what kind of coating can I place on the Aluminum on the inside to slow exposure to corrosion.
What can I treat the Bearing Carrier with Marine Aluminum primer and paint? Can I put a coating of Sharkhide or other treatment in the lower to help it.
Can I fill in the extraction threaded holes to make it easier to remove later? Als it a recommended that I use Aircraft gasket compound on the seal?
These are picture of my parts
Than you for your help.

 

[timguy]

I use a high quality aluminum paint, plenty of anti seize on all fasteners, and a couple of fresh sacrificial zinc units fastened on each side of the cavitation plate in about the center on top. Be sure to keep o-ring areas coated with anti seize or similar corrosion inhibitant as well, I would not use a sealant unless its needed to repair or fill a pitted area. As you know, keep motor flushed out with fresh water after use and spray accessible areas with a good anti corrosion product, or even WD-40. When you install the prop, coat the shaft liberally with anti seize. For cleaning your housing, you can get a mini blaster cup that hooks to your air compressor, do that after you have manually removed the heavy debris. If there is pitting on the o-ring area, you can repair that with a high quality epoxy like Marinetech or JB Weld. Apply with a putty knife and screed it off carefully, then when dry fashion a piece of 180 to 240 grit, wet or dry, onto a can or something just the right diameter to fit inside. Use water to help make a beautiful final finish for the O- ring area. Housings are very expensive and you must not assemble it if there is any chance for water infestation. I did repairs in south Florida for awhile, but here in Minnesota, corrosion is of little concern. Maybe some other techs can address your concerns as I am not the best with corrosion protection. Good luck.