1981 Johnson 25hp anode placement

[14valco]

Hi, This is my first post. I've been soaking up info here for a while. I have a 1981 Johnson 25hp that I have recently purchased to use mainly in saltwater on an aluminum boat. I cannot find a zinc anode on the motor anywhere, so I would like to install one. My service manual (seloc) does not show where the zinc should be installed. Any tips would be greatly appreciated. Thanks.

 

[tashasdaddy]

Re: 1981 Johnson 25hp anode placement

i do not see one on the BRP diagram either.

 

[Vic.S]

Re: 1981 Johnson 25hp anode placement

You could however bolt a small bar anode on the cavitation plate if you see any need for it. Dont forget it must make good electrical contact with the surface to which is its bolted.

 

[14valco]

Re: 1981 Johnson 25hp anode placement

Thanks for the replies, guys.

Do you think one is necessary for my situation? The boat will never be kept in the water - always just day use in saltwater with a thorough freshwater rinse afterwards.

Would putting a zinc on ther transom of the boat be a better or equally effective option than mounting one on the engine?

 

[Vic.S]

Re: 1981 Johnson 25hp anode placement

I'd probably only fit an anode if I noticed any problems with corrosion. But it would be simple enough to fit one as a precautionary measure

Anodes on the hull of the dinghy are another matter. They would protect the aluminium hull but not necessarily the outboard. There must be an good low resistance connection between the anode and what it is to protect. I'd assume that the rubber bushes in the outboard mountings will electrically insulate it from the transom bracket and therefore from the dinghy hull and any anodes fitted to that.