Corrosion/Pitting issue/?

[Numlaar]

Hey all,

I am working on a 1977 70HP Evinrude... The motor runs ok, (needs carbs overhauled, some wiring updating, impeller, shift shaft seal, etc.).

But my concern is, the mid section (and lower unit in particular) have some pretty heavy corrosion on them...

I am wanting to know if I sand blast it, re-zinc chromate and paint, if you think this well present any problems as far as integrity... or over the long haul...

For the most part, they are only surface pock marks maybe 1/32 to 1/16 inch deep... but on the lower unit gear housing part there are some that are pretty bad... possibly even up to 1/8" deep...

I've never had a motor that was corroded this bad, so I don't really know if this will be a big problem or not...

Before I sink any money into getting it up to snuff, I wanted your input on the casing corrosion.

Lower unit (worse part):

Overview of mid/lower unit:

and a close up view of where i took a little sandpaper to some of the pock marks:

Thanks in advance for your feedback!

Num

 

[tashasdaddy]

Re: Corrosion/Pitting issue/?

looks like it had a previous life in salt water. i would clean it the best you can, and paint it as you suggested. i don't know about sand blasting aluminum.

 

[Numlaar]

Re: Corrosion/Pitting issue/?

Thanks TD! One reply is better than none

Yes the hull was bottom painted, so I assume it sat in SW for quite some time...

I have a portable personal sandblaster, and have used it on aluminum before without any problems, great for stripping paint/corrosion in hard to get at places, (like the mounting bracket), but I will test it on the skeg first (since it needs a re-working anyways).

One more quick question if I may...

Do you think I should fill the pits with something like JB Weld, to level them back off before priming/painting, or should I just clean them out good, prime and paint?

Reason I ask is, the Zinc Chromate would bond better to just the aluminum, but for the long haul, it may be better to have the pits filled? (but the primer wouldnt stick as well to those spots)...

Sorry for the questions, done lots of work on the "inside", but never had one so rough looking on the "outside" before

Thanks!
Num

 

[Numlaar]

Re: Corrosion/Pitting issue/?

Gonna start on this in just a little bit... any additional comments/replies?


Thanks so much!

Num

 

[tashasdaddy]

Re: Corrosion/Pitting issue/?

primer it then fill if you want, JB weld sticks to almost anything.

 

[Numlaar]

Re: Corrosion/Pitting issue/?

Thanks TD you're the best!