Fresh-water flushing a raw water system?
 

"Jeffrey P. Vasquez"
wrote in message
...
Hi all,

I am advised to flush a raw-water cooling system on a Yanmar
2GM with fresh
water. I have a couple of questions on execution to any kind
soul that can
offer some advice.

I'm thinking of running a dock hose down and hooking it up to
the hose
coming off the through-hull intake, turning the faucet on,
starting the
engine and just letting it go. However, I'm concerned about
overpressuring
the system and filling the water lift to the point it dumps
into the
engine. Is this a valid concern? Is there a better way to
accomplish this?
There's always positive pressure on the system from the
through-hull
anyway, so I'm assuming as long as I'm pressurizing it from
upstream of the
water pump, I'm safe. True?

When we were running the Volvo that was raw water cooled, there
was an attachment, in the water line inboard of the strainer that
allowed for flushing. About a quarter turn on the fresh water
hose was sufficient for enough cooling. It also worked when you
went to the hard for the winter as it was an easy way to get
antifreeze into the cooling system.

Leanne

Fresh-water flushing a raw water system?
 

you wanna do that BE SURE your engine is running. Otherwise, you will fill
your waterlife muffler until it overflows back into the exhaust manifold and
down one or more of the open exhaust valves, to either hydrolock when you start
the engine or seize the engine with salt water corrosion interally.

When we were running the Volvo that was raw water cooled, there
was an attachment, in the water line inboard of the strainer that
allowed for flushing. About a quarter turn on the fresh water
hose was sufficient for enough cooling. It also worked when you
went to the hard for the winter as it was an easy way to get
antifreeze into the cooling system.

Leanne

Fresh-water flushing a raw water system?
 

you wanna do that BE SURE your engine is running. Otherwise, you will fill
your waterlife muffler until it overflows back into the exhaust manifold and
down one or more of the open exhaust valves, to either hydrolock when you start
the engine or seize the engine with salt water corrosion interally.

When we were running the Volvo that was raw water cooled, there
was an attachment, in the water line inboard of the strainer that
allowed for flushing. About a quarter turn on the fresh water
hose was sufficient for enough cooling. It also worked when you
went to the hard for the winter as it was an easy way to get
antifreeze into the cooling system.

Leanne

Fresh-water flushing a raw water system?
 

On Mon, 26 Jan 2004 23:17:52 -0500, "Leanne" wrote:


When we were running the Volvo that was raw water cooled, there
was an attachment, in the water line inboard of the strainer that
allowed for flushing. About a quarter turn on the fresh water
hose was sufficient for enough cooling. It also worked when you
went to the hard for the winter as it was an easy way to get
antifreeze into the cooling system.

Leanne


If one were to introduce fresh water from the hose to a T after the
salt water strainer (with a valve in the fresh water inlet, of course,
to shut off when not flushing), many good things would happen at once.

You'd be providing fresh water in the intake of the engine water
pump.....flushing the engine.

You'd be BACKFLUSHING the intake system and strainer, probably blowing
out the crap in the strainer back overboard.

The backflushing of the intake with fresh water would eliminate any
"pressure" from the hose as the system would be wide open to the sea.
There wouldn't be any pressure to worry about.

In all honesty, this isn't my idea. My Mercury Sport Jet 175 in my
Sea Ray Sea Rayder F16XR2 is fresh water flushed this way. The only
difference is it has no water pump to buy impellers for. 35 PSI of
seawater pressurizes the water jacket from the BIG pump under the
stern. It simply has a pipe pointing into the 60 gallons per second
pressurized water stream just aft of the stator inside the nozzle's
pressure chamber.

There's no reason not to put a T with a ball valve to the fresh water
hose tap in the hose between the strainer and the water pump. I,
personally, like the idea of flushing out the salt in ANY cooling
system after use. Most yachtsmen, who are too lazy to eliminate the
water ingestion into their diesel tanks by filling them after use,
wouldn't flush the engine, either. To many, engines are just
disposables, anyway. The water jacket, all its fittings and the main
jet pump on "Tess Tickles Too", after 6 years of salt water use, look
just like the first day I launched it.....just because it's flushed
after each use before being stored. It's stupid to leave salt
corroding away the inside of an expensive diesel engine, eating away
at the zinc pencils, when you're not using it.....


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 Mon, 26 Jan 2004 23:17:52 -0500, "Leanne" wrote:


When we were running the Volvo that was raw water cooled, there
was an attachment, in the water line inboard of the strainer that
allowed for flushing. About a quarter turn on the fresh water
hose was sufficient for enough cooling. It also worked when you
went to the hard for the winter as it was an easy way to get
antifreeze into the cooling system.

Leanne


If one were to introduce fresh water from the hose to a T after the
salt water strainer (with a valve in the fresh water inlet, of course,
to shut off when not flushing), many good things would happen at once.

You'd be providing fresh water in the intake of the engine water
pump.....flushing the engine.

You'd be BACKFLUSHING the intake system and strainer, probably blowing
out the crap in the strainer back overboard.

The backflushing of the intake with fresh water would eliminate any
"pressure" from the hose as the system would be wide open to the sea.
There wouldn't be any pressure to worry about.

In all honesty, this isn't my idea. My Mercury Sport Jet 175 in my
Sea Ray Sea Rayder F16XR2 is fresh water flushed this way. The only
difference is it has no water pump to buy impellers for. 35 PSI of
seawater pressurizes the water jacket from the BIG pump under the
stern. It simply has a pipe pointing into the 60 gallons per second
pressurized water stream just aft of the stator inside the nozzle's
pressure chamber.

There's no reason not to put a T with a ball valve to the fresh water
hose tap in the hose between the strainer and the water pump. I,
personally, like the idea of flushing out the salt in ANY cooling
system after use. Most yachtsmen, who are too lazy to eliminate the
water ingestion into their diesel tanks by filling them after use,
wouldn't flush the engine, either. To many, engines are just
disposables, anyway. The water jacket, all its fittings and the main
jet pump on "Tess Tickles Too", after 6 years of salt water use, look
just like the first day I launched it.....just because it's flushed
after each use before being stored. It's stupid to leave salt
corroding away the inside of an expensive diesel engine, eating away
at the zinc pencils, when you're not using it.....


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 Mon, 26 Jan 2004 22:32:38 -0400, "Ken Heaton"
wrote:



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 Mon, 26 Jan 2004 22:32:38 -0400, "Ken Heaton"
wrote:



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?
 

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

On Mon, 26 Jan 2004 23:17:52 -0500, "Leanne" wrote:


When we were running the Volvo that was raw water cooled, there
was an attachment, in the water line inboard of the strainer that
allowed for flushing. About a quarter turn on the fresh water
hose was sufficient for enough cooling. It also worked when you
went to the hard for the winter as it was an easy way to get
antifreeze into the cooling system.

Leanne


If one were to introduce fresh water from the hose to a T after the
salt water strainer (with a valve in the fresh water inlet, of course,
to shut off when not flushing), many good things would happen at once.

You'd be providing fresh water in the intake of the engine water
pump.....flushing the engine.

You'd be BACKFLUSHING the intake system and strainer, probably blowing
out the crap in the strainer back overboard.

The backflushing of the intake with fresh water would eliminate any
"pressure" from the hose as the system would be wide open to the sea.
There wouldn't be any pressure to worry about.

In all honesty, this isn't my idea. My Mercury Sport Jet 175 in my
Sea Ray Sea Rayder F16XR2 is fresh water flushed this way. The only
difference is it has no water pump to buy impellers for. 35 PSI of
seawater pressurizes the water jacket from the BIG pump under the
stern. It simply has a pipe pointing into the 60 gallons per second
pressurized water stream just aft of the stator inside the nozzle's
pressure chamber.

There's no reason not to put a T with a ball valve to the fresh water
hose tap in the hose between the strainer and the water pump. I,
personally, like the idea of flushing out the salt in ANY cooling
system after use. Most yachtsmen, who are too lazy to eliminate the
water ingestion into their diesel tanks by filling them after use,
wouldn't flush the engine, either. To many, engines are just
disposables, anyway. The water jacket, all its fittings and the main
jet pump on "Tess Tickles Too", after 6 years of salt water use, look
just like the first day I launched it.....just because it's flushed
after each use before being stored. It's stupid to leave salt
corroding away the inside of an expensive diesel engine, eating away
at the zinc pencils, when you're not using it.....


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?
 

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

On Mon, 26 Jan 2004 23:17:52 -0500, "Leanne" wrote:


When we were running the Volvo that was raw water cooled, there
was an attachment, in the water line inboard of the strainer that
allowed for flushing. About a quarter turn on the fresh water
hose was sufficient for enough cooling. It also worked when you
went to the hard for the winter as it was an easy way to get
antifreeze into the cooling system.

Leanne


If one were to introduce fresh water from the hose to a T after the
salt water strainer (with a valve in the fresh water inlet, of course,
to shut off when not flushing), many good things would happen at once.

You'd be providing fresh water in the intake of the engine water
pump.....flushing the engine.

You'd be BACKFLUSHING the intake system and strainer, probably blowing
out the crap in the strainer back overboard.

The backflushing of the intake with fresh water would eliminate any
"pressure" from the hose as the system would be wide open to the sea.
There wouldn't be any pressure to worry about.

In all honesty, this isn't my idea. My Mercury Sport Jet 175 in my
Sea Ray Sea Rayder F16XR2 is fresh water flushed this way. The only
difference is it has no water pump to buy impellers for. 35 PSI of
seawater pressurizes the water jacket from the BIG pump under the
stern. It simply has a pipe pointing into the 60 gallons per second
pressurized water stream just aft of the stator inside the nozzle's
pressure chamber.

There's no reason not to put a T with a ball valve to the fresh water
hose tap in the hose between the strainer and the water pump. I,
personally, like the idea of flushing out the salt in ANY cooling
system after use. Most yachtsmen, who are too lazy to eliminate the
water ingestion into their diesel tanks by filling them after use,
wouldn't flush the engine, either. To many, engines are just
disposables, anyway. The water jacket, all its fittings and the main
jet pump on "Tess Tickles Too", after 6 years of salt water use, look
just like the first day I launched it.....just because it's flushed
after each use before being stored. It's stupid to leave salt
corroding away the inside of an expensive diesel engine, eating away
at the zinc pencils, when you're not using it.....


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?
 

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.