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engine overheating
On 19 Jan 2004 06:19:16 -0800, (jzlatar-genesis)
wrote: 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 The mixing elbow is a known weak point in small Yanmars. This is the place the raw water enters the exhaust. It's supposed to be good for about 500 hrs or 6-7 years, whichever comes first. My experience was with a 3GM30F, but I believe that the 2GM20F is quite similar. Find the raw water exit from the heat exchanger and trace it to the exhaust pipe. On most boats, the mixing elbow is shaped like an upside down "U", but it could be just a pipe slanting downward away from the engine. Pull the water hose off of this fitting to see if there is any flow at this point. If there is, you've found the problem, or at least one problem. Don't try to rod out the mixing elbow to get the water flowing again. Just replace it. If you're going to try to replace it yourself, remove the entire exhaust pipe from where it is bolted to the exhaust manifold at the back of the heat exchanger. It's easier and safer than trying to work on it in place. Don't forget that you'll need a new gasket. For the "U" shaped mixing elbow, I seem to recall that there is an adapter with a reverse thread that has to be removed. Good luck, and let us know how it goes. __________________________________________________ __________ 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/ |
engine overheating
On 19 Jan 2004 06:19:16 -0800, (jzlatar-genesis)
wrote: 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 The mixing elbow is a known weak point in small Yanmars. This is the place the raw water enters the exhaust. It's supposed to be good for about 500 hrs or 6-7 years, whichever comes first. My experience was with a 3GM30F, but I believe that the 2GM20F is quite similar. Find the raw water exit from the heat exchanger and trace it to the exhaust pipe. On most boats, the mixing elbow is shaped like an upside down "U", but it could be just a pipe slanting downward away from the engine. Pull the water hose off of this fitting to see if there is any flow at this point. If there is, you've found the problem, or at least one problem. Don't try to rod out the mixing elbow to get the water flowing again. Just replace it. If you're going to try to replace it yourself, remove the entire exhaust pipe from where it is bolted to the exhaust manifold at the back of the heat exchanger. It's easier and safer than trying to work on it in place. Don't forget that you'll need a new gasket. For the "U" shaped mixing elbow, I seem to recall that there is an adapter with a reverse thread that has to be removed. Good luck, and let us know how it goes. __________________________________________________ __________ 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/ |
engine overheating
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engine overheating
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engine overheating
"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 |
engine overheating
"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 |
engine overheating
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? |
engine overheating
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? |
engine overheating
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 |
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