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A
boat I bought has an older V-8 stern-drive engine with a closed cooling
system. What do I have to know about this kind of system and, in particular,
how the heat exchanger works? P.L., via e-mail
Your
closed cooling system is actually two separate systems: the raw-water
system, which uses seawater, and the freshwater system, which uses coolant
like your car. The freshwater loop circulates coolant inside the engine
and around the exhaust manifolds, then pipes it to the heat exchanger,
where heat is transferred to seawater via copper tubing. Because no seawater
enters the engine, corrosion is significantly reduced, and because the
coolant is thermostatically controlled—again, like your car—engine
operating temperature is optimized for better combustion efficiency. The
loop is also pressurized, usually to 14 psi, which raises the boiling
point of the coolant, allowing for higher operating temperatures than
with raw water and further increasing efficiency.
As far
as maintenance is concerned, keep an eye on the raw-water system—especially
zincs and exhaust elbows—as it will be susceptible to corrosion
from the saltwater. Regularly check hoses and hose clamps, as well as
seals and gaskets, for leakage. Inspect your seacock and raw-water pump
also.
We’re
getting a restricted water flow from our shower due to what looks like
a deposit buildup. What can we do to prevent this? B.G.,
via e-mail
The
mineral deposits come from hard water. To eliminate it you’ll have
to “soften” the water—lower its pH. The best way to
do this on a boat is by installing a cartridge filter designed for this
purpose. This is a relatively easy job, and by following the instructions
supplied with any of the units on the market, you should be able to do
it yourself.
You
can remove the residue by spraying the shower head with a product such
as Tilex, then scrubbing it with a toothbrush. If the buildup is particularly
heavy, remove the shower head and give it a more thorough cleaning inside
and out with the cleaning product. If you have a chrome shower head, try
soaking it overnight in a plastic bag filled with vinegar. A thorough
cleaning the next day with freshwater should do the trick. If you have
a brass or brass-plated fixture, do not use vinegar on it, as this will
ruin the finish. Keep at it with the Tilex-type cleaning product.
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