I've never opened the heat exchanger on my Yanmar - I've done it on a Westerbeke
without too much hassle. You should be able to remove the end caps while its on
the engine. However, pull the hose that feeds the elbow and repeat the flow
test. This will tell you where the problem is. Its a bit of a pain because
the elbow fitting has a little ridge on it - this might be a good time to add a
"hose pick" to the tool box. Its like a screwdriver with a bent point for a
tip - you work it around to loosen the hose.

On other thing to invest in is a parts book. This includes blowup diagrams of
everything so you can see what you're up against. Torrenson is a good source,
as is Mack Boring or Mastry in the USA.

-jeff




"jzlatar-genesis" wrote in message
m...
"Jeff Morris" wrote in message
...
You should be able to verify the intake end, including the pump, simply by
disconnecting the pump output and turning the engine over for a few seconds
with
the compression releases open. It should pump a good stream immediately. I
assume you have done that from your comment of "pump is working."

The next step is the heat exchanger, which can be clogged, and following
that is
the exhaust elbow. If you have flow from the pump, you can disconnect the
line
from the heat exchanger to the elbow and turn it over again.

One of my engines carbons up the elbow so quickly enough that I pull it and
scrape it out every year or two. Its only a 1 hour job if you have the
gaskets
and the wrenches that can reach the nuts. Its also possible that the exhaust
pipe or muffler has a problem, but the engine wouldn't start if the exhaust
was
actually clogged.

-jeff



"Leanne" wrote in message
...

"Ray D" rayd at gis.net wrote in message
...
Clogged raw water intake?

I would also check the raw water strainer and when the impeller
was changed, was it whole or was there a piece missing that could
have moved into the cooling system.

Leanne

"jzlatar-genesis" wrote in message
om...
I have a yanmar 2GM20F installed in a Plenamar 300 with the
following
problem, No water coming out of the exhaust pipe with the
result of
overheating and the pump is working with a new impeller, what
could be
the reason for it and the solution.
Thanks in advance
Jzlatar-geminis

Thanks for the prompt response.
yes I disconnect the pump output and turn the engine over for a few
seconds with
the compression releases open. I have a good stream immediately, for that
reason know that the pump is working, when I change the impeller the old one was
intact.
Regarding the muffler, I presume that is working because the fumes
come out, if the heat exchanger,is clogged, that means that I have to
open the engine?

Jorge

You're right except that the exhaust elbow isn't part of the muffler (assuming
he actually has a muffler).

And his engine is a 2GM20F which is fresh water cooled, and has a heat exchanger
bolted on (but certainly distinct from) the manifold.


"Rich Hampel" wrote in message
...
In article ,
jzlatar-genesis wrote:

Regarding the muffler, I presume that is working because the fumes
come out,
NO NO NO NO NO NO ..... fumes AND water need to come out of the exhaust
system. If you have water up to the engine as per your prior
inspection, then open/disconnect the water exit hose of the exhaust
manifold; if flow then you probably have a 'salted' injection elbow, if
no flow then you probably have a fouled exhaust manifold. Cast irion
exhaust manifolds can fail in two ways: corrosion of the base metal
that issues huge platelettes' of rust that lodge in and block the flow
channels ..... or the deposition of carbonate salts (boiler scale
fouling).

What engine do you have?



if the heat exchanger,is clogged, that means that I have to
open the engine?

You're right except that the exhaust elbow isn't part of the muffler (assuming
he actually has a muffler).

And his engine is a 2GM20F which is fresh water cooled, and has a heat exchanger
bolted on (but certainly distinct from) the manifold.


"Rich Hampel" wrote in message
...
In article ,
jzlatar-genesis wrote:

Regarding the muffler, I presume that is working because the fumes
come out,
NO NO NO NO NO NO ..... fumes AND water need to come out of the exhaust
system. If you have water up to the engine as per your prior
inspection, then open/disconnect the water exit hose of the exhaust
manifold; if flow then you probably have a 'salted' injection elbow, if
no flow then you probably have a fouled exhaust manifold. Cast irion
exhaust manifolds can fail in two ways: corrosion of the base metal
that issues huge platelettes' of rust that lodge in and block the flow
channels ..... or the deposition of carbonate salts (boiler scale
fouling).

What engine do you have?



if the heat exchanger,is clogged, that means that I have to
open the engine?

On Mon, 19 Jan 2004 16:40:56 -0500, "Jeff Morris"
wrote:

And his engine is a 2GM20F which is fresh water cooled, and has a heat exchanger
bolted on (but certainly distinct from) the manifold.
Not sure what you meant by "distinct", but the manifold is part of the
heat exchanger assembly. The manifold is at the bottom of the
exchanger in the fresh water reservoir.
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

On Mon, 19 Jan 2004 16:40:56 -0500, "Jeff Morris"
wrote:

And his engine is a 2GM20F which is fresh water cooled, and has a heat exchanger
bolted on (but certainly distinct from) the manifold.
Not sure what you meant by "distinct", but the manifold is part of the
heat exchanger assembly. The manifold is at the bottom of the
exchanger in the fresh water reservoir.
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

On Mon, 19 Jan 2004 16:28:18 -0500, "Jeff Morris"
wrote:

I've never opened the heat exchanger on my Yanmar - I've done it on a Westerbeke
without too much hassle. You should be able to remove the end caps while its on
the engine. However, pull the hose that feeds the elbow and repeat the flow
test. This will tell you where the problem is. Its a bit of a pain because
the elbow fitting has a little ridge on it - this might be a good time to add a
"hose pick" to the tool box. Its like a screwdriver with a bent point for a
tip - you work it around to loosen the hose.

On other thing to invest in is a parts book. This includes blowup diagrams of
everything so you can see what you're up against. Torrenson is a good source,
as is Mack Boring or Mastry in the USA.

Good advice. Also, the Yanmar Service Guide is excellent, and not too
expensive. For instance, it tells you exactly what volume of water
you should be pumping.

For the original poster, opening the heat exchanger is usually pretty
easy, but I think it's your last resort. Since you say you are
getting no waterflow at all, the heat exchanger core is not my first
guess for the problem. It has a lot of small tubes, any one of which
is easy to clog, but the rest would still be open. The core is over
$1000 to replace, so I wouldn't screw with it unless I TOTALLY knew
what I was doing.

If you do have to do it, you'll probably need to remove both end caps.
Look carefully at the caps and the gaskets and the packing. You'll be
glad when it comes time to put everything back together. If you're
lucky, the core will slide right out. If not, you'll need to force it
with something like a large wooden dowel. It's a tight fit by design.
If some deposits have built up around the core, it can be a real pain.
Be careful. $1000! Theoretically, the core can slide out either
direction, but the engine box will probably leave you only one way to
go. You'll probably need to remove the exhaust pipe as well as the
end caps, so this might be a good time to replace the mixing elbow we
talked about.

The question now is what are you going to do with the core. You can
rod it out, carefully. The copper tubes are not really strong. If
you need to clean it, you can take it to a radiator shop as long as
they don't use acid. A good acid bath will leave you with an
interesting metal tube to play with after you install the new core you
bought for over $1000. (Have I mentioned that it's over $1000?) You
might try Marsolve, but I have no experience with it.

Finally, internet advice is worth what you paid for it. If you bugger
it up, it's not my fault!

__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

On Mon, 19 Jan 2004 16:28:18 -0500, "Jeff Morris"
wrote:

I've never opened the heat exchanger on my Yanmar - I've done it on a Westerbeke
without too much hassle. You should be able to remove the end caps while its on
the engine. However, pull the hose that feeds the elbow and repeat the flow
test. This will tell you where the problem is. Its a bit of a pain because
the elbow fitting has a little ridge on it - this might be a good time to add a
"hose pick" to the tool box. Its like a screwdriver with a bent point for a
tip - you work it around to loosen the hose.

On other thing to invest in is a parts book. This includes blowup diagrams of
everything so you can see what you're up against. Torrenson is a good source,
as is Mack Boring or Mastry in the USA.

Good advice. Also, the Yanmar Service Guide is excellent, and not too
expensive. For instance, it tells you exactly what volume of water
you should be pumping.

For the original poster, opening the heat exchanger is usually pretty
easy, but I think it's your last resort. Since you say you are
getting no waterflow at all, the heat exchanger core is not my first
guess for the problem. It has a lot of small tubes, any one of which
is easy to clog, but the rest would still be open. The core is over
$1000 to replace, so I wouldn't screw with it unless I TOTALLY knew
what I was doing.

If you do have to do it, you'll probably need to remove both end caps.
Look carefully at the caps and the gaskets and the packing. You'll be
glad when it comes time to put everything back together. If you're
lucky, the core will slide right out. If not, you'll need to force it
with something like a large wooden dowel. It's a tight fit by design.
If some deposits have built up around the core, it can be a real pain.
Be careful. $1000! Theoretically, the core can slide out either
direction, but the engine box will probably leave you only one way to
go. You'll probably need to remove the exhaust pipe as well as the
end caps, so this might be a good time to replace the mixing elbow we
talked about.

The question now is what are you going to do with the core. You can
rod it out, carefully. The copper tubes are not really strong. If
you need to clean it, you can take it to a radiator shop as long as
they don't use acid. A good acid bath will leave you with an
interesting metal tube to play with after you install the new core you
bought for over $1000. (Have I mentioned that it's over $1000?) You
might try Marsolve, but I have no experience with it.

Finally, internet advice is worth what you paid for it. If you bugger
it up, it's not my fault!

__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

You could be right - I stupidly left my Yanmar books on the boat which is now
sealed up!

But still, the actual heat exchanger tubes can be pulled out of the assembly and
cleaned out. I didn't think they could get "salted."

"Glen "Wiley" Wilson" wrote in message
...
On Mon, 19 Jan 2004 16:40:56 -0500, "Jeff Morris"
wrote:

And his engine is a 2GM20F which is fresh water cooled, and has a heat
exchanger
bolted on (but certainly distinct from) the manifold.
Not sure what you meant by "distinct", but the manifold is part of the
heat exchanger assembly. The manifold is at the bottom of the
exchanger in the fresh water reservoir.
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

You could be right - I stupidly left my Yanmar books on the boat which is now
sealed up!

But still, the actual heat exchanger tubes can be pulled out of the assembly and
cleaned out. I didn't think they could get "salted."

"Glen "Wiley" Wilson" wrote in message
...
On Mon, 19 Jan 2004 16:40:56 -0500, "Jeff Morris"
wrote:

And his engine is a 2GM20F which is fresh water cooled, and has a heat
exchanger
bolted on (but certainly distinct from) the manifold.
Not sure what you meant by "distinct", but the manifold is part of the
heat exchanger assembly. The manifold is at the bottom of the
exchanger in the fresh water reservoir.
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

I have been trying to get the manual or part catalog for the Yanmar
2GM20F but in Santiago Chile is a bit hard, Y have ordered it to
Yanmar directly. My question...Does any body have a photocopy that can
send me to my mail? I mean scanned, only the page where the heat
exchange is?

Thanks in advance
Jorge -Genesis