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Lawrence James
 
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Default Flushing the Mercruiser

Flushing with the muffs will flush the entire coling system including the
outdrive. The raw water pump is in the outdrive. Run for about 5 minutes
or until the temp gauge shows normal operating temp to insure that the
thermostat opens. You really can't beat this flushing technique, it is
cheap and thorough.

A closed cooling system can increase the life of some of your engine
components. Unfortunately the parts that will deteriorate the fastest in
salt water are the exhaust manifolds and exhaust risers. The combination of
hot exhaust and salt water makes an extra corrosive mix. No closed cooling
system will include the exhaust risers. The raw water from the closed
system heat exchanger is used to cool the risers and then dumps into the
exhaust. Some closed systems will include the exhaust manifolds and some
will not. It takes more cooling capacity to include the exhaust manifolds.
There are different gaskets and hose connections for the exhaust system when
you convert them to a closed system.

In salt water depending on amount of use the life of exhaust risers can be
as little as 3 to 5 years. Manifolds a few years longer. They should be
removed and inspected when they start to reach these ages. The engine cast
iron block its self will wear out long before the effects of corrosion will
matter. There are lots of raw water cooled inboard blocks running around
and sitting in salt water for 20 years or longer.

"Rich" wrote in message
. com...
I'm fairly new to motor boats, we now have a Mercruiser 5.0, operated in
sal****er only. Is there a better way to flush other than the "ears" over
the outdrive? I thought at one time there was some kind of setup to flush
the motor without running it, anyone know for sure?

TIA
Rich