Fresh Water vs. Salt Water motor

Ken O

Ken O

Member
I'm looking at purchasing a C-Dory 22 that has a Yamaha 80 as the main engine. I'm pretty sure this boat has never been in salt water, and I intend to use it in salt water. I understand that Mercury offers a salt water version that has the zincs installed, and maybe has other mods also. Does anyone know if this applies to Yamahas, or are they all "salt water ready." If not, can I add the zincs and whatever else is needed. I'm familiar with outboards, but have never run them in salt water.
 
The type of "zinc" is different for salt and fresh water. Just running the boat in salt water or fresh water and flushing it after ward--leaving the boat out of water should not be a problem....but the zincs should be water specific.

Zinc is salt water, Aluminum is brackish--and some salt water, and Magnesium is for fresh water. The internal and external zincs should be changed as appropriate.
 
I am not an mechanical expert but I think your personal diligence in washing the motor out after each use is a more important factor than buying a “saltwater series” engine.

I rinse my motors out with fresh water after each use and then use a product called “salt-away” in it after that. I also rinse the outside of the engine and spray wd40 around those parts I can wash well.

Obviously fresh water use is better but because I live near the ocean my use is primarily salt. If I restrained my use because it was salt water I would hardly be able to go out!

By doing the above and then changing impeller and thermostat every two years it’s the best that you can do. Other than that life is too short so enjoy what the salt water has to offer!

That’s my take

David and Val
 
"zinc" is really a generic term for a sacrificial anode, though many do contain some zinc. As Bob mentioned, you should use the specific sub-type best suited to your primary type of water use. I believe for saltwater the correct "zinc" is an aluminum alloy less noble than the motor's alloy, not a piece of pure zinc. Check with the mfg. and be sure to get the right type...very important if the boat will be kept in the water for extended periods, esp. in marinas. There is likely a large one on the lower tilt bracket, a couple of small ones at the raw water intakes, and one or more internal anodes protecting the exhaust manifold (ie under the cowling, internal to the engine). There may be others specific to your motor. I suggest you use the product Tef-Gel on the threads of all mounting screws before installation to make removal easier on replacement. Best of luck!!
 
Which raises the question (from a fresh water only guy)... if you're doing the loop do you change "zincs" as you go from fresh to salt water?? Or is the time spent ( a few months perhaps) not significant enough to warrant the change?

Jim
 
JMadden":yvzatzz6 said:
Which raises the question (from a fresh water only guy)... if you're doing the loop do you change "zincs" as you go from fresh to salt water?? Or is the time spent ( a few months perhaps) not significant enough to warrant the change?

Jim
Click to expand...

Where the zincs are going to be most beneficial is along the ICW portion of the route where corrosion is more of a concern. The freshwater portion shouldn't be an issue, just a potential for green algae growth.

We've added some disc shaped sacrificial anodes to the trim tabs, and moor along the ICW on our community dock. Within a few weeks to a month those anodes are almost completely eaten away to nothing and need to be replaced. I would have at least one spare set of those anodes with me and replace them in the water along that route.
 
Saltwater marinas can have a lot of stray current in the water. All the zincs on my motor mount and trim tabs were being eaten so fast in Monterey that I started using the submerged on a cable and clipped to the motor Salty Dog "zinc" left over from my sailboat and now it is doing most of the work.
We have noticed that when we spend most of our time anchored out our zincs need to do very little work.
 
Thinking of going the other way, from Salt to Fresh (at least for half a season) so wondering which of the 3 would be the most useful (as in give up the most -- preventing the most corrosion of the engine and boat metals.

Not sure if that is worded right but I think I should have the most sacrificial of the three, Aluminum, zinc or magnesium. Maybe since most of the time would be in Fresh water I should just change to that one, ("Magnesium is for fresh water'), for that half of the season.

"Zinc is salt water, Aluminum is brackish--and some salt water, and Magnesium is for fresh water"
Click to expand...
 from Bob Austin.

Harvey
SleepyC :moon

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