Flushing the motor in brackish waters

msu1966

I have only sailed in fresh water and I am considering buying a C-22 Cruiser with a Honda 90. The boat has been living in brackish water at a dock on the Hudson River for several years. Can the motor be damaged if it is not flushed until the boat is pulled for the season in the Fall?

Thanks, Ken

Flashyfish · Posted: Tue Aug 05, 2025 10:07 am Post subject:

The easy thing to check are the outboard anodes. If they have been properly maintained and replaced as they wear away, that goes a long way to ensuring limited corrosion damage.
There are external anodes and internal engine anodes, both need to be functional.
If you see lifting or bald spots in the paint on the lower outboard unit, then corrosion is lurking.
There is a lot of internet material about the proper type of anodes for different water conditions.
Zinc for saltwater, aluminum for brackish, salt or freshwater and magnesium for fresh water.

Flashyfish · Posted: Tue Aug 05, 2025 10:15 am Post subject:

The easy thing to check are the outboard anodes. If they have been properly maintained and replaced as they wear away, that goes a long way to ensuring limited corrosion damage.
There are external anodes and internal engine anodes, both need to be functional.
If you see lifting or bald spots in the paint on the lower outboard unit, then corrosion is lurking.
There is a lot of internet material about the proper type of anodes for different water conditions.
Zinc for saltwater, aluminum for brackish, salt or freshwater and magnesium for fresh water.

gstraub · Posted: Wed Aug 06, 2025 5:22 am Post subject:

When we purchased our C-22 it had a Honda 90 and had been used (and still is) on the brackish waters of Chesapeake Bay. I routinely flushed it after use, but not sure the original owner did. After a couple of years, the engine failed due to internal corrosion. We got the boat at a price that planned for eventual re-powering, so it wasn't the end of the world. It wouldn't hurt to have a mechanic look at the engine for piece of mind.

thataway · Posted: Wed Aug 06, 2025 7:08 pm Post subject:

It would depend on the salinity of the area of the Hudson river that boat was used on. I believe this River is tidal, so some may depend on the state of the tide when the engine is last run. I would look at the thermostat. That is the easiest; non distructive way of looing at the water passages.