Most of the pumps I've seen have a pair of rubber seals on the shaft-
one to keep the salt water inside the pump and the other to keep the
oil inside the engine. As you've observed, leaks generally drip from
the gap in the pump housing casting.

As long as the leak is small, this is not a huge problem. However, it
won't cure itself and will only get worse. Once the seal fails
completely, you won't have good cooling flow and you will be stuck.

This is generally a pretty easy repair, once you get the pump separated
from the engine. Be sure to have the new seals in hand before you start
the repair. Depending on the age of the pump, and the amount of grit in
the water, the shaft may be scored/worn in the area of the seals.
Sometimes (eg if you are not near replacement parts) you can polish
this up with emery paper so the new seal will not be trashed.
Otherwise, you should replace the shaft while you have the pump torn
down.

There are a pair of bearings in there as well- getting them
on/off/replaced without messing them up needs some patience and the
right collection of tubes/sockets, etc to drive (or press) things apart
without trashing the bearings. Sometimes you can do the job without
having to mess with the bearings- assuming they are ok.

Water pumps and impellers are a common failure/wear area, so probably a
good place to start doing your own repairs. If you're nervous, you
could save quite a few dollars by just pulling the pump and taking it
along to your mechanic so he can do the job on his bench.

I've done this a couple of times on my Westerbeke- fortunately both
times tied to a nice quiet dock!

John

"John" wrote in message
ups.com...
Most of the pumps I've seen have a pair of rubber seals on the shaft-
one to keep the salt water inside the pump and the other to keep the
oil inside the engine. As you've observed, leaks generally drip from
the gap in the pump housing casting.

As long as the leak is small, this is not a huge problem. However, it
won't cure itself and will only get worse. Once the seal fails
completely, you won't have good cooling flow and you will be stuck.

This is generally a pretty easy repair, once you get the pump separated
from the engine. Be sure to have the new seals in hand before you start
the repair. Depending on the age of the pump, and the amount of grit in
the water, the shaft may be scored/worn in the area of the seals.
Sometimes (eg if you are not near replacement parts) you can polish
this up with emery paper so the new seal will not be trashed.
Otherwise, you should replace the shaft while you have the pump torn
down.

There are a pair of bearings in there as well- getting them
on/off/replaced without messing them up needs some patience and the
right collection of tubes/sockets, etc to drive (or press) things apart
without trashing the bearings. Sometimes you can do the job without
having to mess with the bearings- assuming they are ok.

On the previous engine I had, I bought a rebuild kit usually that had a new
shaft and seals.
I think this is standard for most water pumps. About every third impeller
replacement, I would order the kit.

Leanne
s/v Fundy

On Sat, 24 Jun 2006 17:48:41 -0400, "Leanne" wrote:

On the previous engine I had, I bought a rebuild kit usually that had a new
shaft and seals.
I think this is standard for most water pumps. About every third impeller
replacement, I would order the kit.

Probably good advice since my experience is that water pumps are one
of the first things to fail at approximately 500 to 1000 hours. My
recommendation would be to buy a complete spare pump and rebuild the
old one at your leisure.

By all means, do not ignore the leaking seal. Things will only get
worse and end with a total failure at some inopportune time.

http://www.depcopump.com/home.htm

or

http://www.torresen.com/

These engines were brought in for the Great Lakes and not meant for salt
water use.
Get that leak fixed very quick. The steel tube transferring the lubrication
oil from one side to the other runs under the leak and will rust and let the
lubricating oil drain out and you will run dry that is what happened to me.
Hundred dollars of repair/maintenance is nothing compare to a new engine.
If you do not know your way around diesel get someone that does and pay the
penalty. If you happen to lose you engine power at sea the cost will be
more. The cost for towing a boat in the US is not always free let alone the
aggravation. While you're getting the leak fixed check the lubrication
steel tube and if it is rusted replace it.

"Wayne.B" wrote in message
...
On Sat, 24 Jun 2006 17:48:41 -0400, "Leanne" wrote:

On the previous engine I had, I bought a rebuild kit usually that had a
new
shaft and seals.
I think this is standard for most water pumps. About every third impeller
replacement, I would order the kit.

Probably good advice since my experience is that water pumps are one
of the first things to fail at approximately 500 to 1000 hours. My
recommendation would be to buy a complete spare pump and rebuild the
old one at your leisure.

By all means, do not ignore the leaking seal. Things will only get
worse and end with a total failure at some inopportune time.

http://www.depcopump.com/home.htm

or

http://www.torresen.com/

wrote

These engines were brought in for the Great Lakes and not meant for
salt water use.

They run damn near forever in salt water though. Otherwise, excellent
advice.

BTW do you know if the 2GM20(H) has the oil tube in the same place and
if the pump is the same configuration?

--

Roger Long

If you don't already have the manual(s), you might want to take a look here.
http://www.motoren.ath.cx/
BF


"Roger Long" wrote in message
...
wrote

These engines were brought in for the Great Lakes and not meant for
salt water use.

They run damn near forever in salt water though. Otherwise, excellent
advice.

BTW do you know if the 2GM20(H) has the oil tube in the same place and
if the pump is the same configuration?

--

Roger Long

"Roger Long" wrote in news:rhung.32956$W97.19823
@twister.nyroc.rr.com:

BTW do you know if the 2GM20(H) has the oil tube in the same place and
if the pump is the same configuration?



While we are talking about little Yanmars, let me make a point for all of
you to frequently check the damnable pickup tube in the coolant recovery
tank in indirectly-cooled Yanmars with heat exchanger. The tube is under
the cap, saving them money on having a proper BOTTOM outlet molded into
the tank plastic, itself, that cannot help but pickup any liquids in the
tank.

The tube under the cap starts to leak...or much worse yet falls off into
the tank....allowing, in either case, the heat exchanger to suck air as
it cools down, instead of liquid. The heat exchanger has no trouble when
it's heating putting liquid INTO the tank, but then sucks itself full of
air as it cools. This cycle continues until the heat exchanger is
DANGEROUSLY low on coolant, but when the owner inspects the level in the
tank, it looks like it has PLENTY of coolant from the high level in the
tank. As the level in the heat exchanger gets too low, the engine pukes
STEAM out into the coolant recovery tank and the engine overheats..or
worse.

Make a mark with a grease pencil of the stone cold coolant level after
inspecting the coolant level actually inside the heat exchanger's
pressure cap to make sure it's full. If that cold level ever RISES, your
pickup inside the tank is leaking or has fallen off.

Solution is a new piece of hose inside the cap that does NOT go all the
way to the bottom of the tank to pick up tank crap....5200 sealed to the
cap when it's totally dried because a hose clamp just pinches off the
cheap soft plastic the cap is made from. The 5200 makes a permanent bond
between hose and cap, I know. But, alas, caps are MUCH cheaper than
overheated diesel engines when the tube needs replacing 20 years from
now.

Unwilling to put up with this problem, I solved it permanently by
replacing the whole tank on one boat with a coolant tank out of a
car...properly made to withstand coolant pressure with a sealed cap. It
has the hose coming out the bottom fitting and will PRESSURE FILL the
heat exchanger as its pressure drops, not depend on it sucking fluid
through a straw like Yanmar. His tank was empty as it overheated blowing
steam into the Yanmar tank with the hose fallen off! The Yanmar tank
read FULL!

I'd love to survey the tanks in all the Yanmars in a large marina full of
sailboats to see how widespread the problem is. They should know better.