Dismanteling a Johnson F7B-903 impeller cooling pump
 

Hello ng,

I hate it when this happens: the impellerpump starts to leak salt
water on my engine and everywhere in my bilge.

On my Peugeot 60hp marinised diesel I have a Johnson F7B-903
impellerpump delivering seawater to the heat exchanger. The water- /
oil- simmerrings in this pump start to leak after a few hundred hours.
I had the pump revised/overhauled by a machine shop for good money
only 50 engine hours ago but now I have the same problem again.

I guess I am going to take the shaft out and polish it till it shines
before I put in new oil-simmerrings

Does anybody know if I can dismantle this pump without any
sophisticated tools like a hydraulic press or whatever?
Can I push the shaft out by hand or with a plastic hammer?

Thanks for your time... Any advice is highly appreciated...

Len.

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On Tue, 31 Mar 2009 11:12:51 -0700 (PDT), Len
wrote:

Hello ng,

I hate it when this happens: the impellerpump starts to leak salt
water on my engine and everywhere in my bilge.

On my Peugeot 60hp marinised diesel I have a Johnson F7B-903
impellerpump delivering seawater to the heat exchanger. The water- /
oil- simmerrings in this pump start to leak after a few hundred hours.
I had the pump revised/overhauled by a machine shop for good money
only 50 engine hours ago but now I have the same problem again.

I guess I am going to take the shaft out and polish it till it shines
before I put in new oil-simmerrings

Does anybody know if I can dismantle this pump without any
sophisticated tools like a hydraulic press or whatever?
Can I push the shaft out by hand or with a plastic hammer?

Thanks for your time... Any advice is highly appreciated...

Len.

The shaft will have to be pressed out of the bearings but (if I
remember correctly) it isn't difficult. But more to the point, there
is no reason for a pump to leak after a few hours of running. Most of
them don't leak after several years. Examine the shaft for wear and by
the way, parts are expensive.

I had a similar problem and discovered that the people that re-built
the pump simply installed new seals and the problem was the shaft
which had a groove worn in it where the seal was mounted. A new shaft
was a hundred dollars, or so, if I remember.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On Tue, 31 Mar 2009 11:12:51 -0700 (PDT), Len
wrote:

Hello ng,

I hate it when this happens: the impellerpump starts to leak salt
water on my engine and everywhere in my bilge.

On my Peugeot 60hp marinised diesel I have a Johnson F7B-903
impellerpump delivering seawater to the heat exchanger. The water- /
oil- simmerrings in this pump start to leak after a few hundred hours.
I had the pump revised/overhauled by a machine shop for good money
only 50 engine hours ago but now I have the same problem again.

I guess I am going to take the shaft out and polish it till it shines
before I put in new oil-simmerrings

Does anybody know if I can dismantle this pump without any
sophisticated tools like a hydraulic press or whatever?
Can I push the shaft out by hand or with a plastic hammer?


If you are in the USA you might want to give these guys a call:

http://www.depcopump.com/

They stock all kinds of pumps and are expert at rebuilding them. You
should also consider that you may have some other issue that is
causing the pump seals to fail prematurely.

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On 31 mrt, 21:08, Bruce In Bangkok wrote:
On Tue, 31 Mar 2009 11:12:51 -0700 (PDT), Len
wrote:

The shaft will have to be pressed out of the bearings but (if I
remember correctly) it isn't difficult.

Thanks Bruce,
By not difficult you mean I might be able to push the shaft out using
some leverage?
If so I'm planning to construct some tool with a seat on the shaft
which I can push down with a lever.
The question is can I produce the necessary kgf's to get things
moving.

is no reason for a pump to leak after a few hours of running. Most of
them don't leak after several years. Examine the shaft for wear and by
the way, parts are expensive.
I had a similar problem and discovered that the people that re-built
the pump simply installed new seals and the problem was the shaft
which had a groove worn in it where the seal was mounted. A new shaft
was a hundred dollars, or so, if I remember.

I hope I'll be able 1) to move the shaft 1mm up or down so
the surface in contact with the seal will be "new" and therefore
undamaged
or 2) ask a machineshop to remove a tiny bit on the spot where the
seal-
ring touches, afterwards polish it to a stunning shine....

I am looking forward to the several years of use without leaking like
you mentioned....

Thanks for your time.
Len.
on board s/v Present
At the moment in Carriacou

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On 31 mrt, 21:33, Wayne.B wrote:

If you are in the USA you might want to give these guys a call:

http://www.depcopump.com/

They stock all kinds of pumps and are expert at rebuilding them. *You
should also consider that you may have some other issue that is
causing the pump seals to fail prematurely.

Thanks, I sent them an email.
When you say "other issues" do you have something specific in mind?
Bearings are new, engine runs fine.

Regards, Len.

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On Tue, 31 Mar 2009 18:57:11 -0700 (PDT), Len
wrote:

On 31 mrt, 21:33, Wayne.B wrote:

If you are in the USA you might want to give these guys a call:

http://www.depcopump.com/

They stock all kinds of pumps and are expert at rebuilding them. *You
should also consider that you may have some other issue that is
causing the pump seals to fail prematurely.

Thanks, I sent them an email.
When you say "other issues" do you have something specific in mind?
Bearings are new, engine runs fine.


One possibility is that something is causing the pump to run hotter
than designed. That could be caused by a restricted intake or clogged
heat exchanger for example. If it is belt driven then it could be a
belt tension or pulley alignment issue.

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On Tue, 31 Mar 2009 18:39:23 -0700 (PDT), Len
wrote:

I hope I'll be able 1) to move the shaft 1mm up or down so
the surface in contact with the seal will be "new" and therefore
undamaged
or 2) ask a machineshop to remove a tiny bit on the spot where the
seal-
ring touches, afterwards polish it to a stunning shine....



You really need to get a new shaft. Anything else is going to be a
short term band-aid.

Dismanteling a Johnson F7B-903 impeller cooling pump
 

"Len" wrote in message
...
I hope I'll be able 1) to move the shaft 1mm up or down so
the surface in contact with the seal will be "new" and therefore
undamaged
or 2) ask a machineshop to remove a tiny bit on the spot where the
seal-
ring touches, afterwards polish it to a stunning shine....

I am looking forward to the several years of use without leaking like
you mentioned....

Thanks for your time.
Len.
on board s/v Present
At the moment in Carriacou

If you do that it will be slightly undersize and therefore slack in the seal
and therefore likely to still leak.
You could do as you say and then have it plated oover with hard chrome and
reground to correct size but that will probably cost as much as a new shaft.

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On Tue, 31 Mar 2009 18:39:23 -0700 (PDT), Len
wrote:

On 31 mrt, 21:08, Bruce In Bangkok wrote:
On Tue, 31 Mar 2009 11:12:51 -0700 (PDT), Len
wrote:

The shaft will have to be pressed out of the bearings but (if I
remember correctly) it isn't difficult.

Thanks Bruce,
By not difficult you mean I might be able to push the shaft out using
some leverage?
If so I'm planning to construct some tool with a seat on the shaft
which I can push down with a lever.
The question is can I produce the necessary kgf's to get things
moving.

is no reason for a pump to leak after a few hours of running. Most of
them don't leak after several years. Examine the shaft for wear and by
the way, parts are expensive.
I had a similar problem and discovered that the people that re-built
the pump simply installed new seals and the problem was the shaft
which had a groove worn in it where the seal was mounted. A new shaft
was a hundred dollars, or so, if I remember.

I hope I'll be able 1) to move the shaft 1mm up or down so
the surface in contact with the seal will be "new" and therefore
undamaged
or 2) ask a machineshop to remove a tiny bit on the spot where the
seal-
ring touches, afterwards polish it to a stunning shine....

I am looking forward to the several years of use without leaking like
you mentioned....

Thanks for your time.
Len.
on board s/v Present
At the moment in Carriacou

As I remember I disassembled the two pumps on the dock with hand tools
- probably a plastic faced hammer and a punch, and after getting new
parts reassembled them the same way. A week or so later we departed
Singapore bound for Phuket, Thailand - say a thousand miles. Since we
reached Thailand the boat is being "renovated", for want of a better
word, so the engines have only been run for a bit every few weeks. No
leaks to date.

I see no reason that you can't rebuild them with common hand tools.
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Dismanteling a Johnson F7B-903 impeller cooling pump
 

On Wed, 01 Apr 2009 00:17:13 -0400, Wayne.B
wrote:

On Tue, 31 Mar 2009 18:39:23 -0700 (PDT), Len
wrote:

I hope I'll be able 1) to move the shaft 1mm up or down so
the surface in contact with the seal will be "new" and therefore
undamaged
or 2) ask a machineshop to remove a tiny bit on the spot where the
seal-
ring touches, afterwards polish it to a stunning shine....



You really need to get a new shaft. Anything else is going to be a
short term band-aid.


I second the suggestion. My experience is that unless you rebuild with
new, or like new, parts you will have problems in a very short time.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)