Electrolysis

[LaneyAnne]

I have a 25hp Evinrude Electric start on a 14' aluminum that stays in the water of my canal. Last summer my prop and much of my lower unit corroded beyond belief, even with a brand new zinc attached! The prop was shot and I could break chunks off with my fingers. I managed to clean up the rest of it and bought a new prop. I thought the reason was keeping my battery hooked up all the time, there must be a draw somewhere and that is doing it so now I unhook the positive cable when not in use. Well, it appears to be happening again but not as severe.

Any thoughts?? Getting desperate and discouraged!! Props are $120!!!!

Thanks in advance for any help or advice.

 

[DKennimer]

Re: Electrolysis

Electrolysis is corrosion caused by two dis-similar metals. If in fact it is electrolysis than look for some type of die-electric fitting. They are used every day for water heaters.

 

[boobie]

Re: Electrolysis

You said canal. Do you have any other boats close to you or do you have any 120 volt service or lights down where the the boat is kept ?

 

[bigrockets]

Re: Electrolysis

Is the water in your canal salt water or brackish? Are there any electrical wires touching the water or ground nearby such as a ground rod for an electrical panel ground? Do you tilt the engine up out of the water when not using the boat? Is the engine bonded to the hull of the boat or insulated by a wooden transom?

 

[LaneyAnne]

Re: Electrolysis

Thanks for the replies guys...

There aren't any power sources or other boats in the water near mine. Unless there is a hidden ground somewhere off of the seawall that I don't know about. I live on a small island where there is current, especially when the freighter go by and push/pull the water. Not salt water or brackish. I have no lighting near the seawall or boat, and I do tilt it up and out (for the most part) of the water. It is a longshaft so the bottom of the prop and skeg are still in the water a little. Yes, it has a wooden transom as well.

I am still stumped, thanks for the input guys! I really appreciate it.