I recently noticed the absence of water exiting the engine exhaust hole - 1984 Universal M-18, Oberdorfer sea water pump. I installed a new impeller, made sure the lines going into and out of the pump are clear. Next I pulled the end cap off of the heat exchanger but could not see an obstruction or look into the hole. That's where I stopped. Two questions: 1.) If I remove the heat exchanger will this involve draining/replacing the fresh water/anti-freeze. 2.) Any other suggestions ?
Sea Water not flowing out of exhaust
- Thread starter waclancy
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I would do the following...
First, no water from the exhaust means no cooling. Not good. I would verify that the seacock and raw water strainer are clear. I have experienced a seacock plugged with seaweed that will pass no water. Same for the strainer. If those are OK, and if you have run the engine with the new impeller for more than a minute, then I would check the new impeller again. It only takes a minute or two to destroy a new impeller with no water. Given that you can get water to flow into the seacock and out of the strainer, I would disconnect the output of the raw wter pump and attach a hose and put it to a bucket. Check again for water exiting the pump. Continue this process. You will find the reason. It's not rocket science. If you must remove the heat exchanger, you will disconnect it from the fresh water cooling, so yes, you will need to drain and refill the FW coling system. When you replaced the impeller was it destroyed? if one or more of the blades were missing, did you find and account for all of the missing parts? It is possible that a missing impeller blade can travel to EITHER the intake or output side of the pump and cause a clog. The blade can travel more than a few inches. So when you say that the pump lines were clear, how far from the pump did you check?
First, no water from the exhaust means no cooling. Not good. I would verify that the seacock and raw water strainer are clear. I have experienced a seacock plugged with seaweed that will pass no water. Same for the strainer. If those are OK, and if you have run the engine with the new impeller for more than a minute, then I would check the new impeller again. It only takes a minute or two to destroy a new impeller with no water. Given that you can get water to flow into the seacock and out of the strainer, I would disconnect the output of the raw wter pump and attach a hose and put it to a bucket. Check again for water exiting the pump. Continue this process. You will find the reason. It's not rocket science. If you must remove the heat exchanger, you will disconnect it from the fresh water cooling, so yes, you will need to drain and refill the FW coling system. When you replaced the impeller was it destroyed? if one or more of the blades were missing, did you find and account for all of the missing parts? It is possible that a missing impeller blade can travel to EITHER the intake or output side of the pump and cause a clog. The blade can travel more than a few inches. So when you say that the pump lines were clear, how far from the pump did you check?
Make sure that after you open the strainer that you get a good seal when you put the top back on. If you don't it will allow air in and and you won't get a vacuum to draw the water through the raw water system. I have this problem and found that by finger tightning the thumb nut on the strainer as tight as I can by hand and then giving it about a quarter turn with pliers creates a good seal.
Check the Mixing Elbow
This happened to me once, and after confirming that no clog existed in the intake hose, through hull or pump output, using the process suggested by Rich, I checked the mixing elbow. It must have clogged from exhaust build-up. I was able to unclog it without removal from my Yanmar 2GM30, but you may need to remove from your Universal.
This happened to me once, and after confirming that no clog existed in the intake hose, through hull or pump output, using the process suggested by Rich, I checked the mixing elbow. It must have clogged from exhaust build-up. I was able to unclog it without removal from my Yanmar 2GM30, but you may need to remove from your Universal.
Oberdorfer
On my Oberdorfer pump there is a small (maybe 1/4"inch) bleed on top of the pump which I remove whenever I change or work on the impeller. I find it removes any air pocket inside the impeller housing. If water doesn't come out quickly then at least you know the problem is upstream.
On my Oberdorfer pump there is a small (maybe 1/4"inch) bleed on top of the pump which I remove whenever I change or work on the impeller. I find it removes any air pocket inside the impeller housing. If water doesn't come out quickly then at least you know the problem is upstream.
Will, disconnect hose from outlet
of heat exchanger, then open sea cock and start engine. If you get water coming out of exchanger, then everything upriver from that is OK, and it is probably the mixing elbow. When I was in your situation I ruled out the sea strainer and then went to the impeller. It took two hours to replace impeller and didn't solve the problem. Then I disconnected the outflow hose from the exchanger and got water flow, so I knew it was the downstream mixing elbow. Should have done the 5 minute disconnect of the outflow of the exchnager first.
of heat exchanger, then open sea cock and start engine. If you get water coming out of exchanger, then everything upriver from that is OK, and it is probably the mixing elbow. When I was in your situation I ruled out the sea strainer and then went to the impeller. It took two hours to replace impeller and didn't solve the problem. Then I disconnected the outflow hose from the exchanger and got water flow, so I knew it was the downstream mixing elbow. Should have done the 5 minute disconnect of the outflow of the exchnager first.
How far from pump
Rich,I removed the hose from the pump to the exchanger - clear - I removed the hose from exchanger to exhaust fitting - clear. I like your idea of testing the pump with hose(s) disconnected into a bucket. Next i'll likely move to the mixing elbow. Also, the impeller I removed was distorted but in tact. John - I'll look for that bleed - didn't notice it first time. I'll be at the boat this weekend. Will update ya'll after. Thanks so much for the ideas - I couldn't ask for better support.
Rich,I removed the hose from the pump to the exchanger - clear - I removed the hose from exchanger to exhaust fitting - clear. I like your idea of testing the pump with hose(s) disconnected into a bucket. Next i'll likely move to the mixing elbow. Also, the impeller I removed was distorted but in tact. John - I'll look for that bleed - didn't notice it first time. I'll be at the boat this weekend. Will update ya'll after. Thanks so much for the ideas - I couldn't ask for better support.
Bob V.
Before you take to the water again with a wet suit, there are a couple of things you can try first. I use my inflatable dinghy foot pump to "back-blow" the raw water input. Simply put it over the intake nipple (on the INSIDE of the boat), open the seacock and give it a good push. This may clear out any obstructions. Another method that has worked for other people is to use their air horn in the same method. That has worked for others, also (just block your ears, first).
Before you take to the water again with a wet suit, there are a couple of things you can try first. I use my inflatable dinghy foot pump to "back-blow" the raw water input. Simply put it over the intake nipple (on the INSIDE of the boat), open the seacock and give it a good push. This may clear out any obstructions. Another method that has worked for other people is to use their air horn in the same method. That has worked for others, also (just block your ears, first).
Strainer ?
I'll have to check for a strainer. Is this standard equipment ? Opening the cabin door to the engine I see the black seacock valve, a hose attached to it going to the Oberdorfer pump inlet, but again, from memory I don't remember seeing any other item there. Can I assume there is some type of screen or "grate" in the hull at the inlet for the seacock valve ?
I'll have to check for a strainer. Is this standard equipment ? Opening the cabin door to the engine I see the black seacock valve, a hose attached to it going to the Oberdorfer pump inlet, but again, from memory I don't remember seeing any other item there. Can I assume there is some type of screen or "grate" in the hull at the inlet for the seacock valve ?
Strainer *should* be standard equipment.....
If you don't have one, get it. Seaweed and other floating junk can take out a raw water pump in nothing flat. You may have a grate similiar to the ones I installed on the outside of your hull, but that doesn't negate the need for a strainer between the seacock and the pump.
If you don't have one, get it. Seaweed and other floating junk can take out a raw water pump in nothing flat. You may have a grate similiar to the ones I installed on the outside of your hull, but that doesn't negate the need for a strainer between the seacock and the pump.
Air pump...
Like Paul A., I keep a 12 volt tire inflator pump aboard for such problems. I also have a short piece of hose with tire valve clamped in one end that fits the water intakes on the boat. Close the thru-hull, pull off the hose, clamp on the stubby one, attach the air pump until you get to about 50 lbs PSI on its gauge, then flip the thru-hull valve open. It's like firing a torpedo and the results are instantaneous. Close the valve, reattach the hose and off you go.
Like Paul A., I keep a 12 volt tire inflator pump aboard for such problems. I also have a short piece of hose with tire valve clamped in one end that fits the water intakes on the boat. Close the thru-hull, pull off the hose, clamp on the stubby one, attach the air pump until you get to about 50 lbs PSI on its gauge, then flip the thru-hull valve open. It's like firing a torpedo and the results are instantaneous. Close the valve, reattach the hose and off you go.
And, re the HX
When you take it off 1. you can plug the fresh water lines with plugs so you don't have to replace the antifreeze 2. Check in the inlet and outlet ports of the HX. While the HX may be just fine inside, our experience is that the inlet ports get blocked by the accumulation of salt. So the guts are fine, but no water is getting through. It is were my boat, I'd remove the HX and see what's happening, first. Your replacement of your impeller indicates that the next step is the HX, unless, as suggested, you elbow is caked up.
When you take it off 1. you can plug the fresh water lines with plugs so you don't have to replace the antifreeze 2. Check in the inlet and outlet ports of the HX. While the HX may be just fine inside, our experience is that the inlet ports get blocked by the accumulation of salt. So the guts are fine, but no water is getting through. It is were my boat, I'd remove the HX and see what's happening, first. Your replacement of your impeller indicates that the next step is the HX, unless, as suggested, you elbow is caked up.
My M18 had a similar problem...
I had water pumping ot the pump, going through the system and coming out of the heat exchanger but it was just beyond the heat exchanger and into the exhaust manifold where it was plugged up. Ended up opening the various port holes and used stiff wire to poke around, break things up and get things flowing again. Worked fine ever since. Rick
I had water pumping ot the pump, going through the system and coming out of the heat exchanger but it was just beyond the heat exchanger and into the exhaust manifold where it was plugged up. Ended up opening the various port holes and used stiff wire to poke around, break things up and get things flowing again. Worked fine ever since. Rick
Torpedo Dan.....
What a great idea!! I need to hold myself back from running to my shop to make up one of these "tools" right now!! Seriously, this sounds like a wonderful addition to my arsenal of unique tools. Thanks for sharing!!
What a great idea!! I need to hold myself back from running to my shop to make up one of these "tools" right now!! Seriously, this sounds like a wonderful addition to my arsenal of unique tools. Thanks for sharing!!
Air cooled
Lister in England made a line of air cooled marine diesels & perhaps they still are available. Air cooled engines are inherently noisier as the don't have the extra mass required for water jacketing and the coolant to absorb the engine noise. Also, the ducting for cooling air has to be fairly large and would require some very careful planning to avoid creating a passage that could swamp the boat in dirty weather. I've only seen them used in open boats like ship's life boats & workboats. They're cheaper to make and to install, so there are probably others made to target installations in the Third World but they're not a good choice for aux. power in a sailboat.
Lister in England made a line of air cooled marine diesels & perhaps they still are available. Air cooled engines are inherently noisier as the don't have the extra mass required for water jacketing and the coolant to absorb the engine noise. Also, the ducting for cooling air has to be fairly large and would require some very careful planning to avoid creating a passage that could swamp the boat in dirty weather. I've only seen them used in open boats like ship's life boats & workboats. They're cheaper to make and to install, so there are probably others made to target installations in the Third World but they're not a good choice for aux. power in a sailboat.
Rich...
As they say, "Necessity is the mother of invention"... I have found that sharing is a way in which we all learn and become better for it. You're most welcome!
As they say, "Necessity is the mother of invention"... I have found that sharing is a way in which we all learn and become better for it. You're most welcome!
Thank you, all
I agree Rich -- what great ideas. I really appreciate all of your ideas and the time you took to respond. I'm going to the boat tomorrow. I'll log in later and let you all know what I find. Have a great weekend everyone. Will
I agree Rich -- what great ideas. I really appreciate all of your ideas and the time you took to respond. I'm going to the boat tomorrow. I'll log in later and let you all know what I find. Have a great weekend everyone. Will
Problem solved
When I installed the impeller, being alone at the time, I had assumed the proper rotation direction of the pump. I lubricated the impeller, bent a few of the "vanes" relative to the assumed rotation and installed the cover. Well, I was wrong - so the problem all along has been the impeller installed with the "vanes" bent and working against the proper rotation, so apparently it was just enough to reduce the pumps efficiency to move the seawater. Now, I did remove the heat exchanger and found what sounded like rocks inside, but turned out to be stones of some sort, from a calcium or element buildup, because as I bumped the exchanger, and shook it, the stones began to break apart. I then removed the drain plug and the pieces fell out. I also ran a wire rod down each of the exchanger's holes to be sure each was clear. Once re-installed and all connections secure I started the engine and now have the desired result. One more thing though, something I didn't mention on this forum, I couldn't install the e-clip on the end of the pump shaft, meant to secure the impeller I suppose, but it doesn't seem to affect pump performance. I believe I can slightly pull the shaft out enough to install the clip but I really don't see the need for the clip as the pump is self priming and the impeller is completely enclosed between the rear wall and the cover of the pump. Thanks for everyones feedback and If I can be of assistance please let me know - clancy151@cox.net Will
When I installed the impeller, being alone at the time, I had assumed the proper rotation direction of the pump. I lubricated the impeller, bent a few of the "vanes" relative to the assumed rotation and installed the cover. Well, I was wrong - so the problem all along has been the impeller installed with the "vanes" bent and working against the proper rotation, so apparently it was just enough to reduce the pumps efficiency to move the seawater. Now, I did remove the heat exchanger and found what sounded like rocks inside, but turned out to be stones of some sort, from a calcium or element buildup, because as I bumped the exchanger, and shook it, the stones began to break apart. I then removed the drain plug and the pieces fell out. I also ran a wire rod down each of the exchanger's holes to be sure each was clear. Once re-installed and all connections secure I started the engine and now have the desired result. One more thing though, something I didn't mention on this forum, I couldn't install the e-clip on the end of the pump shaft, meant to secure the impeller I suppose, but it doesn't seem to affect pump performance. I believe I can slightly pull the shaft out enough to install the clip but I really don't see the need for the clip as the pump is self priming and the impeller is completely enclosed between the rear wall and the cover of the pump. Thanks for everyones feedback and If I can be of assistance please let me know - clancy151@cox.net Will
Mmmm, I always thought the vanes would.....
align themselves when the pump was turned. I'm *sure* I have bent them wrong sometime or another and never had a problem. E-clip? Don't know what this is, but it must be there for a good reason. I would look into that issue some more.
align themselves when the pump was turned. I'm *sure* I have bent them wrong sometime or another and never had a problem. E-clip? Don't know what this is, but it must be there for a good reason. I would look into that issue some more.
E-Clip
On many of the Orberdorfer pumps the shaft turns in bushing. The e-clip at the impeller end keeps the shaft in the pump housing. If the pump is engine driven (rather than belt driven) you may have to pull the pump off to fully seat the shaft, then the e-clip should go right on.
On many of the Orberdorfer pumps the shaft turns in bushing. The e-clip at the impeller end keeps the shaft in the pump housing. If the pump is engine driven (rather than belt driven) you may have to pull the pump off to fully seat the shaft, then the e-clip should go right on.
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