Fresh-water flushing a raw water system?
 

hey, you guys, kindly knock it off. You don't have a clew what you are talking
about in this case.

Leanne, it will cost you several thousand dollars to repair the damage there
guys are trying to do to your engine. Just send me $2,000 (in used bills,
please) and I will walk over to St Patrick's cathedral and light a candle for
you. That way you will save a LOT of money over a rebuild.


We usually do this by extending the thru hull hose with another short piece
of hose up into a 5 gallon bucket set in the cockpit. We then start the
engine and let the raw water pump move the water through. We keep the
bucket full by leaving the dock hose running into the bucket, if it
overflows it just runs out the cockpit drains. No chance of
over-pressurising anything or damaging your raw water pump. As we live in
Canada and so have to winterise this system, we then throw some antifreeze
into the bucket and let that pump through until it starts to come out the
exhaust, shut it down and that's it for the season.

This is the recommended method. You can make it easier by putting a
Y-valve above the thru-hull, The hose on the Y can have a garden hose
end on it and can be looped above the waterline if you are paranoid.

An added, if emergency, benefit of this is that you can wrap some sort
of strainer (a piece of nylon mesh, whatever) on the end of this and
in an emergency can use this hose to drain your bilges using the
engine's water pump. It's not as motivated as a man with a bucket, but
it will go longer while you are dealing with getting the boat in
order.

R.

Fresh-water flushing a raw water system?
 

On 27 Jan 2004 15:22:20 GMT, (JAXAshby) wrote:

larry, do that as you suggest on a Yanmar with a waterlift muffler and you will
cause some expensive to repair damage.

How? The engine is RUNNING during the flush. Feeding fresh water
into the stream into the RUNNING water pump simply replaces salt with
fresh. Any fresh water not pumped into the engine by the engine's OWN
water pump (whos impeller, by the way, meters how much water it passes
because my way has no hose pressure on it to speak of)...any excess
fresh water is simply fed backwards through the seawater strainer,
probably clearing it of the crap and run overboard unless the intake
or strainer is clogged, of course.

As the engine is RUNNING, there is no waterbox flooding or exhaust
backup because of the exhaust pressure of the engine. No excessive
water pressure is applied to the engine, any more than the water the
seawater pump on the engine imparts on it.

How's it going to destroy the engine this way. Simply turn off the
hose as soon as you stop the engine......before the seawater is pumped
through it, again.

You'd probably NEVER have to flush or core the cooling system if you
did it every time you used it.....even on closed systems with a heat
exchanger!


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!

Fresh-water flushing a raw water system?
 

On 27 Jan 2004 15:22:20 GMT, (JAXAshby) wrote:

larry, do that as you suggest on a Yanmar with a waterlift muffler and you will
cause some expensive to repair damage.

How? The engine is RUNNING during the flush. Feeding fresh water
into the stream into the RUNNING water pump simply replaces salt with
fresh. Any fresh water not pumped into the engine by the engine's OWN
water pump (whos impeller, by the way, meters how much water it passes
because my way has no hose pressure on it to speak of)...any excess
fresh water is simply fed backwards through the seawater strainer,
probably clearing it of the crap and run overboard unless the intake
or strainer is clogged, of course.

As the engine is RUNNING, there is no waterbox flooding or exhaust
backup because of the exhaust pressure of the engine. No excessive
water pressure is applied to the engine, any more than the water the
seawater pump on the engine imparts on it.

How's it going to destroy the engine this way. Simply turn off the
hose as soon as you stop the engine......before the seawater is pumped
through it, again.

You'd probably NEVER have to flush or core the cooling system if you
did it every time you used it.....even on closed systems with a heat
exchanger!


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!

Fresh-water flushing a raw water system?
 

*pressure* water into the raw water intake can indeed overfill the waterlift
muffler once the engine is not running, and it doesn't take long.

As far as "cleaning out" the cooling system by flushing after use, that just
doesn't play. The cooling system gets clogged up by a.) "carbonates" loosely
meaning the various salts that plate out on the cooling system walls as hot
salt water (which has LOTs minerals in it), and b.) crud -- like silt -- that
falls out of the water as it flows through the cooling system.

And Yanmar raw water cooled engines were more suseptable to both a.) and b.)
than other raw water cooled engines of the era.

And again, do NOT turn pressure water on when the engine is not running.
Better is to run the water into a 5-gallon bucket and suck it from the bucket
into the engine.

your explanation was not clear that the engine MUST be running.

On 27 Jan 2004 15:22:20 GMT, (JAXAshby) wrote:

larry, do that as you suggest on a Yanmar with a waterlift muffler and you
will
cause some expensive to repair damage.

How? The engine is RUNNING during the flush. Feeding fresh water
into the stream into the RUNNING water pump simply replaces salt with
fresh. Any fresh water not pumped into the engine by the engine's OWN
water pump (whos impeller, by the way, meters how much water it passes
because my way has no hose pressure on it to speak of)...any excess
fresh water is simply fed backwards through the seawater strainer,
probably clearing it of the crap and run overboard unless the intake
or strainer is clogged, of course.

As the engine is RUNNING, there is no waterbox flooding or exhaust
backup because of the exhaust pressure of the engine. No excessive
water pressure is applied to the engine, any more than the water the
seawater pump on the engine imparts on it.

How's it going to destroy the engine this way. Simply turn off the
hose as soon as you stop the engine......before the seawater is pumped
through it, again.

You'd probably NEVER have to flush or core the cooling system if you
did it every time you used it.....even on closed systems with a heat
exchanger!


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!

Fresh-water flushing a raw water system?
 

*pressure* water into the raw water intake can indeed overfill the waterlift
muffler once the engine is not running, and it doesn't take long.

As far as "cleaning out" the cooling system by flushing after use, that just
doesn't play. The cooling system gets clogged up by a.) "carbonates" loosely
meaning the various salts that plate out on the cooling system walls as hot
salt water (which has LOTs minerals in it), and b.) crud -- like silt -- that
falls out of the water as it flows through the cooling system.

And Yanmar raw water cooled engines were more suseptable to both a.) and b.)
than other raw water cooled engines of the era.

And again, do NOT turn pressure water on when the engine is not running.
Better is to run the water into a 5-gallon bucket and suck it from the bucket
into the engine.

your explanation was not clear that the engine MUST be running.

On 27 Jan 2004 15:22:20 GMT, (JAXAshby) wrote:

larry, do that as you suggest on a Yanmar with a waterlift muffler and you
will
cause some expensive to repair damage.

How? The engine is RUNNING during the flush. Feeding fresh water
into the stream into the RUNNING water pump simply replaces salt with
fresh. Any fresh water not pumped into the engine by the engine's OWN
water pump (whos impeller, by the way, meters how much water it passes
because my way has no hose pressure on it to speak of)...any excess
fresh water is simply fed backwards through the seawater strainer,
probably clearing it of the crap and run overboard unless the intake
or strainer is clogged, of course.

As the engine is RUNNING, there is no waterbox flooding or exhaust
backup because of the exhaust pressure of the engine. No excessive
water pressure is applied to the engine, any more than the water the
seawater pump on the engine imparts on it.

How's it going to destroy the engine this way. Simply turn off the
hose as soon as you stop the engine......before the seawater is pumped
through it, again.

You'd probably NEVER have to flush or core the cooling system if you
did it every time you used it.....even on closed systems with a heat
exchanger!


Larry W4CSC

Is it just me or did the US and UK just capture 1/3
of the world's sweetest oil supply? What idiot wants to
GIVE IT BACK?!!