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Old January 5th 10, 07:37 AM posted to rec.boats.cruising
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Default Cooling pump keeps developing a leak

I am having problems with this cooling pump.
http://www.depcopump.com/datasheets/...10-24218-1.pdf
This pump has been overhauled twice and apart from that it has been
serviced with new seals but it keeps developing a leak. Last time (2
months after overhaul) the seawater crept through 2 seals into the
engine block. I had to take out 2 gallons of salt water. Now it starts
again to drip. since that last servicing I have only been in clear
seawater.

I'm thinking of :
1) some mechanical ceramic seal that will do the job properly and for
years but I have no clue how to go about that one.
2) removing the waterhoses from this pump and add an electrical pump
with enough capacity and proper alarms and so on.

I would be obliged if you could spill your experience / thoughts
regarding this.

Regards,
Len on board s.v Present,
at the moment in Grenada, W.I.

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Old January 5th 10, 12:07 PM posted to rec.boats.cruising
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Default Cooling pump keeps developing a leak

On Mon, 4 Jan 2010 22:37:45 -0800 (PST), Len
wrote:

I am having problems with this cooling pump.
http://www.depcopump.com/datasheets/...10-24218-1.pdf
This pump has been overhauled twice and apart from that it has been
serviced with new seals but it keeps developing a leak. Last time (2
months after overhaul) the seawater crept through 2 seals into the
engine block. I had to take out 2 gallons of salt water. Now it starts
again to drip. since that last servicing I have only been in clear
seawater.

I'm thinking of :
1) some mechanical ceramic seal that will do the job properly and for
years but I have no clue how to go about that one.
2) removing the waterhoses from this pump and add an electrical pump
with enough capacity and proper alarms and so on.

I would be obliged if you could spill your experience / thoughts
regarding this.

Regards,
Len on board s.v Present,
at the moment in Grenada, W.I.


I had a similar problem - rebuilt pump and it leaked soon after. In my
case it was because the shaft was damaged where the seal is
positioned. The repairman installed a new seal which was immediately
ruined by the damaged shaft.

If your pump is located lower then the water line (so that it is self
priming) you can replace the rubber impeller pump with a belt driven
centrifugal pump. I've had one on my boat for about ten years with no
problems to date.

You could also use an electric (rated for constant service) pump but I
am a bit leery of that as the electric pump is constant volume while
engine requirement is variable - more with higher RPM.
Although I had an auxiliary generator that was plumbed that way and
never gave any problems.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)
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Old January 5th 10, 12:34 PM posted to rec.boats.cruising
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Default Cooling pump keeps developing a leak

To overhaul a water pump *IS* to replace the o ring and lip seals,
and ensure the shaft is smooth.

Actions you should consider.
!) Go to a different mechanic.
2) Replace the shaft, seals and o ring and try again
OR
3) Replace the entire pump with the same model.

This time, make sure there is no side force on the drive shaft, and keep
out of shallow sand and grit.

If after doing this you still get less than 12 months service, think
again about another brand of pump.

Brian W
(Worth all of the dough you paid for this advice!)

Len wrote:
I am having problems with this cooling pump.
http://www.depcopump.com/datasheets/...10-24218-1.pdf
This pump has been overhauled twice and apart from that it has been
serviced with new seals but it keeps developing a leak. Last time (2
months after overhaul) the seawater crept through 2 seals into the
engine block. I had to take out 2 gallons of salt water. Now it starts
again to drip. since that last servicing I have only been in clear
seawater.

I'm thinking of :
1) some mechanical ceramic seal that will do the job properly and for
years but I have no clue how to go about that one.
2) removing the waterhoses from this pump and add an electrical pump
with enough capacity and proper alarms and so on.

I would be obliged if you could spill your experience / thoughts
regarding this.

Regards,
Len on board s.v Present,
at the moment in Grenada, W.I.

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Old January 5th 10, 03:01 PM posted to rec.boats.cruising
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Default Cooling pump keeps developing a leak

http://www.depcopump.com/datasheets/...10-24218-1.pdf
This pump has been overhauled twice and apart from that it has been
serviced with new seals but it keeps developing a leak. Last time (2
months after overhaul) the seawater crept through 2 seals into the
engine block. I had to take out 2 gallons of salt water. Now it starts
again to drip. since that last servicing I have only been in clear
seawater.


First of all, make sure that seawater can leak out from between the two seals;
there should be an unblocked outlet to the outside to:
1. prevent water from ever reaching the second seal.
2. clearly show that the first seal is leaking.

Secondly other new seals without survey, are unlikely to last. Look for:
1. rough/damaged surfaces where the seals touch.
2. a loose pump.
3. mis-alignment of the engine and pump axle, or a bent axle.
4. worn axle-bearings allowing to much radial movement for the seals to cope
with.
5. too much pressure on the cooling system due to (partial) blockage blowing
the seals.

Have a nice search (it's freezing here right now!)

Mees de Roo


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Old January 5th 10, 06:01 PM posted to rec.boats.cruising
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Default Cooling pump keeps developing a leak

Sorry I should add to that:
6. Making sure that the engine-blok seal is an oil-lubricated type and the
pump seal is a water lubricated type (some types are both water and oil
lubricated, but if not and if interchangable.....)

What worries me is the fact that water could pass from the pump to the
engine-block seal an further at all; it should leak right into the bilge ?!?
Are you sure about the water following that way an/or is everything
reassembled correctly?

Mees de Roo




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Old January 5th 10, 08:11 PM posted to rec.boats.cruising
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Default Cooling pump keeps developing a leak

Moving the new seals slightly off their current positions on the shaft
may fix the problem. Set the new seals with permatax 1 and use plastic
washers. Space between seals needs to be vented. Or replace the shaft.
E-mail or call Depco pump in Tampa -- they're very helpful. HS Ft.
Lauderdale

On 1/5/2010 1:37 AM, Len wrote:
I am having problems with this cooling pump.
http://www.depcopump.com/datasheets/...10-24218-1.pdf
This pump has been overhauled twice and apart from that it has been
serviced with new seals but it keeps developing a leak. Last time (2
months after overhaul) the seawater crept through 2 seals into the
engine block. I had to take out 2 gallons of salt water. Now it starts
again to drip. since that last servicing I have only been in clear
seawater.

I'm thinking of :
1) some mechanical ceramic seal that will do the job properly and for
years but I have no clue how to go about that one.
2) removing the waterhoses from this pump and add an electrical pump
with enough capacity and proper alarms and so on.

I would be obliged if you could spill your experience / thoughts
regarding this.

Regards,
Len on board s.v Present,
at the moment in Grenada, W.I.


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Old January 5th 10, 08:28 PM posted to rec.boats.cruising
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First recorded activity by BoatBanter: Jul 2006
Posts: 430
Default Cooling pump keeps developing a leak

Len,
Not enough information..... Johnson pumps are bulletproof IF you run them within their design parameters AND it is installed
correctly. You did not mention how it is driven, but if it runs faster than 2000 RPM, you are running this beyond its designed
capability. Bruce offered a good alternative, if the installation is the culprit. There can be a multitude of faults that can
cause early failure. Please be more specific.
Steve

"Len" wrote in message ...
I am having problems with this cooling pump.
http://www.depcopump.com/datasheets/...10-24218-1.pdf
This pump has been overhauled twice and apart from that it has been
serviced with new seals but it keeps developing a leak. Last time (2
months after overhaul) the seawater crept through 2 seals into the
engine block. I had to take out 2 gallons of salt water. Now it starts
again to drip. since that last servicing I have only been in clear
seawater.

I'm thinking of :
1) some mechanical ceramic seal that will do the job properly and for
years but I have no clue how to go about that one.
2) removing the waterhoses from this pump and add an electrical pump
with enough capacity and proper alarms and so on.

I would be obliged if you could spill your experience / thoughts
regarding this.

Regards,
Len on board s.v Present,
at the moment in Grenada, W.I.


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Old January 8th 10, 07:40 PM posted to rec.boats.cruising
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Posts: 18
Default Cooling pump keeps developing a leak

Thanks for the replies.
@Mees,
The seawater in the engine blocks occurred with new, flat faced seals
which I suspect to "aquaplane" and let water through.
These were used by the mechanical shop. I will not use those again and
I'm back to the "V-shaped" seals.

@Steve
I normally run the engines (I have a twin engine motorsailer and BOTH
identical engines show the same problem...) below 2000 rpm.
With the last overhaul, every bearing was replaced even when the
bearing looked and felt OK.

@Bruce
I think your solution is the way I want to go.
Which brand centrifugal pump did you install?
Any pitfalls or more hints come to mind?

TIA, Len.
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Old January 8th 10, 10:28 PM posted to rec.boats.cruising
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First recorded activity by BoatBanter: Jul 2006
Posts: 430
Default Cooling pump keeps developing a leak

Len,
Not engine RPM, I meant pump RPM. Look at the pump drive and calculate drive ratio.
Steve

"Len" wrote in message ...
Thanks for the replies.
@Mees,
The seawater in the engine blocks occurred with new, flat faced seals
which I suspect to "aquaplane" and let water through.
These were used by the mechanical shop. I will not use those again and
I'm back to the "V-shaped" seals.

@Steve
I normally run the engines (I have a twin engine motorsailer and BOTH
identical engines show the same problem...) below 2000 rpm.
With the last overhaul, every bearing was replaced even when the
bearing looked and felt OK.

@Bruce
I think your solution is the way I want to go.
Which brand centrifugal pump did you install?
Any pitfalls or more hints come to mind?

TIA, Len.

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Old January 9th 10, 01:10 AM posted to rec.boats.cruising
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Posts: 576
Default Cooling pump keeps developing a leak

On Fri, 8 Jan 2010 10:40:52 -0800 (PST), Len
wrote:

Thanks for the replies.
@Mees,
The seawater in the engine blocks occurred with new, flat faced seals
which I suspect to "aquaplane" and let water through.
These were used by the mechanical shop. I will not use those again and
I'm back to the "V-shaped" seals.

@Steve
I normally run the engines (I have a twin engine motorsailer and BOTH
identical engines show the same problem...) below 2000 rpm.
With the last overhaul, every bearing was replaced even when the
bearing looked and felt OK.

@Bruce
I think your solution is the way I want to go.
Which brand centrifugal pump did you install?
Any pitfalls or more hints come to mind?

TIA, Len.


I used a centrifugal pump that is made in Thailand, but any well built
pump should suffice. I used a cast iron, 3/4" outlet, pump for about 8
- 9 years. Had some over heating problems and investigation showed
build-up of scale and corrosion in the inlet port of the pump. I
replaces it with a bronze pump, however 8 - 9 years service is not to
be sneered at, I'd reckon, and cheaper too.

In my case I replaced the port fwd. engine mount bracket, that bolts
to the engine, with a fabricated bracket that incorporates a flat
mount surface for the pump. The pump base is slotted to allow some
adjustment but actually, since installation I have never adjusted the
pump or replaced the vee belt that drives it from the engine's front
"fan belt pulley".

I don't remember whether I calculated pump RPM when I originally built
the system but I just had a look at it and I'd "eyeball" the ratio at
about 2 - 3 times engine speed.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)


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