I am desperate to find a marine mechanic who is familiar with Universal Engines on the south shore (Nassau County) of Long Island. The mechanic who I was using did a poor job on diagnosing a problem on my 89 Universal M25XP. He reccomended a re-build due to white smoke coming out of my exhaust. He declined to do the job, but suggested I find someone who does a lot of work on Universals. That advise put me in touch with Hansen Marine in Marblehead, MA and when I described my problem they told me they highly doubted it needed a re-build. The first question they asked was; it is hard to start? When I indicated it has never failed to turn over in three years on the first attempt they said it could not be a compression problem. When I described the white smoke they immediately suggested mixing elbow. I have since had two overheats which somehow self correct. I have replaced every part of the cooling system over last winter, and I know the thermostat, cooling hoses and heat exchanger are in perfect condition. I have cleaned out the raw water filter, never finding anything that would cause a blockage. The raw water pump is brand new, and I have had the fresh water pump pulled out and checked as well. I have canceled my vacation using the boat, and my wife is afraid to take any trips that might require any motoring other than getting out of the slip and through the inlet. I cannot find anyone who will come down to the boat, and motoring to their location is out of the question. The boat is located in Point Lookout, and if anyone can suggest a good mechanic I would be grateful. I do not want to pull the boat for the winter, replace the mixing elbow, muffler and exhaust hose only to find out in the spring that that was not the cause of the white smoke and occassional overheats. I really have reached the desperation point. If the engine requires a re-build fine, I will then explore my options; repair or replace. I do find it hard to believe that a diesel with 850 hours does require a re-build. Just the fact of not knowing is driving me crazy.
Universal Mechanic
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overheating
I can understand your frustration about not knowing the heart of the problem. The white smoke indicates water. Period. What condition is that fuel tank in? It is possible that water is getting in with the diesel. Otherwise you have a gasket issue, and this does not mean a rebuild. The part you mention which strikes me as odd is "I have since had two overheats which somehow self correct." I don't know if that is possible except for a bad/going bad thermostat or pump. Yet I still have to go with a gasket issue. Though I am not a Universal Mechanic. Just a mechanic.
I can understand your frustration about not knowing the heart of the problem. The white smoke indicates water. Period. What condition is that fuel tank in? It is possible that water is getting in with the diesel. Otherwise you have a gasket issue, and this does not mean a rebuild. The part you mention which strikes me as odd is "I have since had two overheats which somehow self correct." I don't know if that is possible except for a bad/going bad thermostat or pump. Yet I still have to go with a gasket issue. Though I am not a Universal Mechanic. Just a mechanic.
Head gasket?
Sounds like a small head gasket leak to me. White smoke means water in the combustion chamber. Is the white smoke continuous? Are you having to refil the fresh cooling water? Also change the mixing elbow. People have already told you that may be the problem. That you can do yourself and if that doesn't fix it, you then know it's the head gasket.
Sounds like a small head gasket leak to me. White smoke means water in the combustion chamber. Is the white smoke continuous? Are you having to refil the fresh cooling water? Also change the mixing elbow. People have already told you that may be the problem. That you can do yourself and if that doesn't fix it, you then know it's the head gasket.
Universal problem
I drained the fuel tank in the spring and replaced with fresh diesel. The thermostat was checked prior to installation in a pot of boiling water and a digital thermometer, it opened around 160 degrees. I also replaced all of the antifreeze, and have not used a drop all season. My oil is also clear of water as far as I can tell. As indicated I also replaced the raw water pump this spring after noticing some salt stains under the pump.
I drained the fuel tank in the spring and replaced with fresh diesel. The thermostat was checked prior to installation in a pot of boiling water and a digital thermometer, it opened around 160 degrees. I also replaced all of the antifreeze, and have not used a drop all season. My oil is also clear of water as far as I can tell. As indicated I also replaced the raw water pump this spring after noticing some salt stains under the pump.
Chief, a couple more questions.
How did the overheat manifest itself? Did the 'radiator' cap blow or did the alarm just sound? If it was just an alarm and all seemed normal, be sure to check for a bare wire from the sender that could be grounding. Also, how much white smoke? There's white smoke and then there's white,,,. Anyway, a little white smoke can be just condensation like you see on your car during cool weather. Let's see (I'm rereading your post)
Oh, did you check your intake through-hull to make sure it's clear?
How did the overheat manifest itself? Did the 'radiator' cap blow or did the alarm just sound? If it was just an alarm and all seemed normal, be sure to check for a bare wire from the sender that could be grounding. Also, how much white smoke? There's white smoke and then there's white,,,. Anyway, a little white smoke can be just condensation like you see on your car during cool weather. Let's see (I'm rereading your post)
Oh, did you check your intake through-hull to make sure it's clear?I had the same problem
I had the same problem last year with my engine. When I took the head off I found a very small break in the forward part of the head gasket. Don't ask me how it got there....don't know. I installed a new gasket and now it's working just fine....no more smoke and temps are steady. You may also want to have the injectors looked at while your head is off. Water realy plays a number on the tips.
I had the same problem last year with my engine. When I took the head off I found a very small break in the forward part of the head gasket. Don't ask me how it got there....don't know. I installed a new gasket and now it's working just fine....no more smoke and temps are steady. You may also want to have the injectors looked at while your head is off. Water realy plays a number on the tips.
Mixing Elbow
Why not follow Hansen Marine's advice and replace the mixing elbow? My overheating was too a problem until I replaced the mixing elbow. I had thought it was a big deal, but it was not costly and did it myself. Check the archives. 800 hours sounds like it is possible. Take it apart and see if it is clogged partially. This is a pretty important of the engine cooling!
Why not follow Hansen Marine's advice and replace the mixing elbow? My overheating was too a problem until I replaced the mixing elbow. I had thought it was a big deal, but it was not costly and did it myself. Check the archives. 800 hours sounds like it is possible. Take it apart and see if it is clogged partially. This is a pretty important of the engine cooling!
Disconnect the raw water intake hose from
through-hull valve and check if sea weed been suck in and clogged the valve or hull strainer. Not too much of sea weed would limite the flow of cooling water and cause white smoke or engine over heating.
through-hull valve and check if sea weed been suck in and clogged the valve or hull strainer. Not too much of sea weed would limite the flow of cooling water and cause white smoke or engine over heating.
Clean the elbow
How many times has that been said? It should be done as part of regular annual maintenance and even if it isn't causing this specific problem, at least you will have eliminated it and you won't have to wonder. If you asked the mechanic, why not do what he said? It is relatively easy and you should do it anyway. Black smoke and loss of power is the usual indication of the plugged elbow. White smoke is more likely an indication of a head gasket or something else making steam.
How many times has that been said? It should be done as part of regular annual maintenance and even if it isn't causing this specific problem, at least you will have eliminated it and you won't have to wonder. If you asked the mechanic, why not do what he said? It is relatively easy and you should do it anyway. Black smoke and loss of power is the usual indication of the plugged elbow. White smoke is more likely an indication of a head gasket or something else making steam.
Mixing elbow?
It's called an exhaust riser. With 850 hours, you should replace it before it goes out on you completely. It happened to me and I wrote it up in Mainsheet magazine (C34 Tech section) a few years ago. PITA. Why wait to haul out to replace it - it goes from the manifold to the hose to the muffler. The weak point is the connection of the water outlet to the hot gas outlet at the weld in the riser. It will GO on you in a heartbeat, right at the weld or close to it. You can order a replacement, already insulated, from Catalina, or have one made up locally. White smoke isn't necessarily bad - we just motored back four hours from race in a friend's boat with white smoke and his engine is fine. What makes you think you have a problem? Other than the intermittent overheats - and anything intermittent means you DO have a problem that needs to be fixed, and it sounds like the next step is the exhaust riser. If that does it, then your problems are over. You seem to have done EVERYTHING necessary except the exhaust riser. Only other thing I can think of for intemrittent overheating - since you replaced the antifreeze, are you sure you got all the air out of the fresh water side? Stu
It's called an exhaust riser. With 850 hours, you should replace it before it goes out on you completely. It happened to me and I wrote it up in Mainsheet magazine (C34 Tech section) a few years ago. PITA. Why wait to haul out to replace it - it goes from the manifold to the hose to the muffler. The weak point is the connection of the water outlet to the hot gas outlet at the weld in the riser. It will GO on you in a heartbeat, right at the weld or close to it. You can order a replacement, already insulated, from Catalina, or have one made up locally. White smoke isn't necessarily bad - we just motored back four hours from race in a friend's boat with white smoke and his engine is fine. What makes you think you have a problem? Other than the intermittent overheats - and anything intermittent means you DO have a problem that needs to be fixed, and it sounds like the next step is the exhaust riser. If that does it, then your problems are over. You seem to have done EVERYTHING necessary except the exhaust riser. Only other thing I can think of for intemrittent overheating - since you replaced the antifreeze, are you sure you got all the air out of the fresh water side? Stu
Elbow is easy to check
White smoke does not always mean head gasket. Black smoke does not always mean the elbow. White smoke could be caused by a semi-plugged elbow. If it is partly plugged, cooling sea water isn't able to make it all the way out the exhaust without part of it turning into steam 1st. The cooling seawater isn't that complicated. It comes in the intake seacock, to the water pump and impeller, to the heat exchanger, to the dry elbow, to the wet U-elbow, to the muffler, to the tailpipe outlet. If your engine is overheating, and you think it may be caused by the seawater cooling, just check all these components. Other than the impeller, the U-elbow is the 2nd most frequent cause of overheating engine. If you idle your engine at low RPMs often, run it high for a few minutes every hour or so. See attached photo from the Yanmar manual.
White smoke does not always mean head gasket. Black smoke does not always mean the elbow. White smoke could be caused by a semi-plugged elbow. If it is partly plugged, cooling sea water isn't able to make it all the way out the exhaust without part of it turning into steam 1st. The cooling seawater isn't that complicated. It comes in the intake seacock, to the water pump and impeller, to the heat exchanger, to the dry elbow, to the wet U-elbow, to the muffler, to the tailpipe outlet. If your engine is overheating, and you think it may be caused by the seawater cooling, just check all these components. Other than the impeller, the U-elbow is the 2nd most frequent cause of overheating engine. If you idle your engine at low RPMs often, run it high for a few minutes every hour or so. See attached photo from the Yanmar manual.
M25Xp Headgasket Replacment
I have replaced all the major items of my cooling system but still it is overheating. Now following the Universal Mechanic thread I am considering that maybe my head gasket is bad how will I detemine this may be the problem. The Local guy that fixes engine is not a Universal guy and knows nothing about my Diesel. Very little white smoke but I am starting to lose coolant but no leaks appear. Any suggestions.
I have replaced all the major items of my cooling system but still it is overheating. Now following the Universal Mechanic thread I am considering that maybe my head gasket is bad how will I detemine this may be the problem. The Local guy that fixes engine is not a Universal guy and knows nothing about my Diesel. Very little white smoke but I am starting to lose coolant but no leaks appear. Any suggestions.
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