zinc plate attached to cavitation plate

[superflydudebike]

I recently purchased a 1986 15 HP Evinrude, made in Canada. I finally figured out what was attached to the cavitation plate - a zinc plate. Does this suggest that this motor was used in saltwater or are these pretty standard on these models? What exactly is the zinc for?

 

[tashasdaddy]

Re: zinc plate attached to cavitation plate

so just add them, for use in marinas, stray current from other boats. the electrolisis, attacks the zinc, instead of the aluminum.

 

[flabum]

Re: zinc plate attached to cavitation plate

Yes, that was standard on those motors for a while. The zinc protects the aluminum from electrolosis in salt water, and they also make them out of magnesium for fresh water use. Do not use the magnesium ones in salt water.