White crystals on engine block?

[mulla]

While cleaning my engine I noticed these weird-looking crystallization in one of the "pits" on the outside of the cylinder head.
Has anyone seen this before or know what it is? When I removed it, it looked like it had corroded and deepened the pit.

https://imgur.com/3CZBO5n

https://imgur.com/6aGxbBo

 

[Old Harry]

Salt ???

 

[RichardS]

Looks like salt corrosion. Particularly prevalent on an alloy casting. Clean it all off and find out where the salty water is dripping from.

Richard

 

[mulla]

Looks like salt corrosion. Particularly prevalent on an alloy casting. Clean it all off and find out where the salty water is dripping from.

Richard

Salt ???

I was thinking of that but I felt like it was too much since all those salt crystals must have come from water standing in that small hole, but then again I've only seen sea salt on cliffs before ?
When thinking about it, the engine must have been left for a while in a position that didn't allow the water to leave the hole.

Should I cover the bare spots off aluminium with a layer of paint to prevent this from happening again?

 

[Praxinoscope]

I agree with the above looks very much like salt water corrosion, there must be a small leak somewhere, not necessarily directly above the point of corrosion, but possibly draining to a point where it drips on the engine.

 

[mulla]

I agree with the above looks very much like salt water corrosion, there must be a small leak somewhere, not necessarily directly above the point of corrosion, but possibly draining to a point where it drips on the engine.

It's a small 2hp outboard so I'm guessing some water dripped through the cowling

 

[dutyhog]

I had that last season. Licking it soon showed it was salt. Eventually traced it to a small crack in salt water hose spraying onto the engine.

 

[mulla]

So what's the opinion on painting the exposed aluminium, paint or just clean?

 

[longjohnsilver]

Salt ???

Yes definitely salt

 

[dutyhog]

So what's the opinion on painting the exposed aluminium, paint or just clean?

I cleaned it off with vinegar then painted with red engine paint (withstands great heat).

 

[mulla]

I cleaned it off with vinegar then painted with red engine paint (withstands great heat).

Cool I guess I'll pick some up next time I'm in town

 

[Iliade]

Hydrated alumina - http://www.almet-marine.com/images/...viour-of-aluminium-in-marine environments.pdf

 

[vyv_cox]

So what's the opinion on painting the exposed aluminium, paint or just clean?

If it has survived many years unpainted it seems pointless to paint it now. If you do, topcoat paint does not adhere to aluminium very well, it needs an etch primer first. That should give it a long life.

 

[LadyInBed]

So what's the opinion on painting the exposed aluminium, paint or just clean?

IMO painting it just traps and hides further corrosion.
I would clean it, give a coat of spray grease, brass wire brush it then rub in another coat of waterproof grease.