surface coating inside the crankcase?

[Pascal]

Is there a special coating, paint or anodizing that evinrude put on the inner surface of the crank case and cooling system??<br /><br />I'm working on a 1976 40 horse power head. I am wondering if a cleanup in an aluminum compatible hot tank solution would hurt anything??<br /><br />Thanks for any guidance you all can give.<br /><br />JD

 

[Paul Moir]

Re: surface coating inside the crankcase?

I don't know about '76 but earlier ones had painted the inside. I've heard two stories about why. One was that somehow the paint insulated the crankcase and therefore kept atomized fuel in suspension better. (If you belive that, I've got some land...) The other was to help seal any porous castings they got. I can't say I've ever seen a porous J/E casting and modern ones don't use the paint.<br />Modern fuels seem to do a really good job of stripping the old paint out, so I don't think that will be a concern.<br /><br />On the other hand, you've got a good mixture of metals there. Aluminium, whatever is in the "brass" babbit labyrinth seal, babbit thrust bearings, steel pins and cast iron bores. That is to say a receipe for a battery and all you need to add is the electrolyte. So just give it a good solvent wash - it's not difficult or time consuming with the right products.