I'm having some problems with my raw water cooled Universal 5411. I fired it up and it would only do a maximum of 2000 rpm in gear but in neutral it would act normal - make it up to 3000rpm. The water pump was hot to the touch. White exhaust seemed greater than normal. A friend suggested I look at the exhaust riser. I took it off and it looked it over - it looked ok to me. When I put the riser back together I noticed the vented loop where the water goes was plugged. When I cleaned out the loop, it had so much rust caked on it I couldn't believe any water could have made it out my exhaust. Thinking this was the problem, I put it back together and fired up the engine again. Same rpm problem. The water pump is hot to the touch. White exhaust seems greater than normal. Could I have a second blockage somewhere? Could the first blockage have caused too much stress on the impellor - could less than normal water flow be the cause of lower rpm's in gear? Could there have been issues with the riser that I just didn't notice? All these problems were not there when I left the boat over the winter (and changed the filters) - could I have not bled the fuel well enough? I need your expertise here guys. Thanks in advance, -Rob
A diesel engine mystery...
- Thread starter Rob 1981 Cat 3019642
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Cooling?
Rob, If your 2000 / 3000 rpm tests were done on a relatively cold engine then I doubt that lack of cooling would have had an effect. Shortage of cooling water normally leads to engine seizure in a very short time and seriously damages the piston and cylinders. Yes the engine will run slowly for a few seconds before it seizes but that is all the notice you are likely to get. Why not check the amount of water coming out of the exhaust? If the outlet is under the counter try looking into a shaving mirror taped on to a stick - yes that is what I do. This can be done alongside the slip and will determine whether the problem is lack of water or not. e.g. stuck thermostat or plugged water inlet filter, though I guess you have looked at these items already. My thoughts are more to do with your fuel supply as, on load, the engine needs more fuel and if it cannot get it then it will not reach the correct revs. I suggest checking the two in line filters. Another cause of low revs and possibly smoke is a fouled prop and the engine is overloaded, though this smoke is normally black. A damaged or leaking cylinder head gasket can also give rise to white smoke and a compression test on the engine will prove this one way or the other. This still leaves the hot water pump. Maybe it always runs hot? Either from its location on the engine, or from the internal friction of the impeller. When you find the cause please let us know. BTW what engine is it? Regards,
Rob, If your 2000 / 3000 rpm tests were done on a relatively cold engine then I doubt that lack of cooling would have had an effect. Shortage of cooling water normally leads to engine seizure in a very short time and seriously damages the piston and cylinders. Yes the engine will run slowly for a few seconds before it seizes but that is all the notice you are likely to get. Why not check the amount of water coming out of the exhaust? If the outlet is under the counter try looking into a shaving mirror taped on to a stick - yes that is what I do. This can be done alongside the slip and will determine whether the problem is lack of water or not. e.g. stuck thermostat or plugged water inlet filter, though I guess you have looked at these items already. My thoughts are more to do with your fuel supply as, on load, the engine needs more fuel and if it cannot get it then it will not reach the correct revs. I suggest checking the two in line filters. Another cause of low revs and possibly smoke is a fouled prop and the engine is overloaded, though this smoke is normally black. A damaged or leaking cylinder head gasket can also give rise to white smoke and a compression test on the engine will prove this one way or the other. This still leaves the hot water pump. Maybe it always runs hot? Either from its location on the engine, or from the internal friction of the impeller. When you find the cause please let us know. BTW what engine is it? Regards,
Right Course
I am thinking that the problem may be on the exhaust side. That rust came from some where. If there is a restriction on the exhaust side it could limit rpms espically when under load (more fuel more exhaust more back pressure). How old is the engine? "White exhaust greater than normal." Is that after the engine is warmed up? All fuel filter where changed you said? If it running I doubt that bleeding is the issue unless it is running rough. Then there is the (shutter) clogged injector possibility. Did something get through when you were changing you filter? Address that one last.
I am thinking that the problem may be on the exhaust side. That rust came from some where. If there is a restriction on the exhaust side it could limit rpms espically when under load (more fuel more exhaust more back pressure). How old is the engine? "White exhaust greater than normal." Is that after the engine is warmed up? All fuel filter where changed you said? If it running I doubt that bleeding is the issue unless it is running rough. Then there is the (shutter) clogged injector possibility. Did something get through when you were changing you filter? Address that one last.
Sounds like more than one problem
I would check the impeller. It may have been damaged by the blocked passage and might account for the white smoke. The low rpm issue may be fuel supply or fouled prop. Then again, it could be a blown head gasket doing both.
I would check the impeller. It may have been damaged by the blocked passage and might account for the white smoke. The low rpm issue may be fuel supply or fouled prop. Then again, it could be a blown head gasket doing both.
Overloaded engine
Rob Any chance you have overloaded the engine with a propeller that is too large? If the engine reaches normal rpm without load (neutral), then I would look at engine loads as possible cause. best of luck
Rob Any chance you have overloaded the engine with a propeller that is too large? If the engine reaches normal rpm without load (neutral), then I would look at engine loads as possible cause. best of luck
A to Z
Morning Rob: Without getting too wordy, start at the intake through hull and work your way all the way through the system to where it exhausts. A dock buddy of mine had an overheat problem on his Yanmar that was wearing everybody out trying to figure out what the ptoblem was. Backflushing, new impellers, heat exchanger cleaning, elbow, etc. and nothing helped. It was finally discovered that an acorn had sucked up into the through hull intake and was lodged there just allowing enough water through to keep the engine from burning up. The white exhaust you are seeing is not smoke, it's steam being generated at the elbow as there is not enough water coming through to keep it properly cool. I suspect that your impeller is also hot to the touch for the same reason. Just another place to check! Good Luck!!
Morning Rob: Without getting too wordy, start at the intake through hull and work your way all the way through the system to where it exhausts. A dock buddy of mine had an overheat problem on his Yanmar that was wearing everybody out trying to figure out what the ptoblem was. Backflushing, new impellers, heat exchanger cleaning, elbow, etc. and nothing helped. It was finally discovered that an acorn had sucked up into the through hull intake and was lodged there just allowing enough water through to keep the engine from burning up. The white exhaust you are seeing is not smoke, it's steam being generated at the elbow as there is not enough water coming through to keep it properly cool. I suspect that your impeller is also hot to the touch for the same reason. Just another place to check! Good Luck!!
Fairly common problem with Univeral engines ....
This will be an intermittant problem IF 'slab rust' develops in the exhaust manifold. Cast Iron when its poured into its mold cools in a 'layered' fashion rendering the casting like an onion .... stratification of the cast iron. When the intake manifold begins to rust the rust will propagate along the zones of stratification and huge 'slabs' of rust will come off; and, will either fall to the bottom of the manifold or will come off and migrate to the area of the water exit .... blocking it or partly blocking it. When you shut down the engine the slabs will sometimes fall to the bottom only to 'rise again' sometime later to block the water exit. This 'condition' is made worse by 'drying out' the engine for long term or winter storage. Cast Iron shouldnt ever be dried out but should be stored with an antifreeze with LOTS of rust inhibitor in it. Normal engine temperatures will form ferrous oxide (black rust) which is a protective coating. Allow the engine to 'dry' and you form ferric rust (red rust) which is very harmful as its less dense than the cast iron and can develop extreme pressure when it forms ---- thus 'peels the onion' and produces the 'slabs'. If this blockage occurs, consider that slab rust has begun to form. Remove the manifold, invert it and with a stiff wire into the water passages go in and break up all the 'slabs'. To insure that the manifold hasnt developed 'pin holes' between the gas side and the water side (can drain back into the cylinders if pinholed - will destroy the cylinders) apply a pressure gage and a water line with a valve, block either the inlet or outlet, apply pressure, shut the valve and watch the gage. If the gage 'drifts' to zero then you have a pin hole (and also should see some water emit over time from the 'gas' side) and you then need a new manifold. How to check for blocked exhaust manifold, etc.: Run engine at near full cruising rpm. Take a bucket of known volume (gallons, etc.) to the exhaust outlet at the stern of the boat, with a stopwatch, etc. record the time that it takes to fill the bucket. Such an engine should have about 1 gallons per minute of cooling water coming out the stern outlet. ANYTHING blocking the cooling water loop will yield less than 1 gallon per minute. So if less than 1 gallon per minute, you have a blockage: slab rust in the exhaust manifold, broken pump impeller lodged in the line, coked water injection nozzle, junk sucked into the loop, etc. etc. etc. For most other engine in boat up to ~35 ft. the cooling water should be about 3 gallons per minute; the 5411 is called the 'pisser' due to its very low cooling water flow. The raw water cooled 5411 (and other raw water cooled engines) also forms carbonates inside the manifold which will eventually block the manifold and cooling water passages inside the engine .... either use a commercial boiler descaling compound (Marsolve or Rydlyme) OR take it off and to a 'radiator' shop and have it cleaned out by ultrasonic methods. Try NOT to use muriatic or hydrochloric acid to 'pickle' the salt out of the engine as they will also dissolve 'base' metal. Use muriatic or hydrochloric only if you cant find a decent boiler descaler. Carbonates are insolubles that 'drop out' from 'raw water' or seawater when its temperature is over 145 degrees F .... this is how 'rocks' are formed in nature. If your engine is 'raw water' cooled, then you should change the thermostat to one that fully opens at 135 degrees F. ... this will allow the cooling water to be UNDER the magic 145 degrees .... not perfect but will much lessen the 'salt' / carbonate build up. Dont ever drain the water to store a cast iron engine ... fill it with 50:50 antifreeze with lots of rust inhibiter to keep the ferrous (black/good/protective) rust intact. Good hunting.
This will be an intermittant problem IF 'slab rust' develops in the exhaust manifold. Cast Iron when its poured into its mold cools in a 'layered' fashion rendering the casting like an onion .... stratification of the cast iron. When the intake manifold begins to rust the rust will propagate along the zones of stratification and huge 'slabs' of rust will come off; and, will either fall to the bottom of the manifold or will come off and migrate to the area of the water exit .... blocking it or partly blocking it. When you shut down the engine the slabs will sometimes fall to the bottom only to 'rise again' sometime later to block the water exit. This 'condition' is made worse by 'drying out' the engine for long term or winter storage. Cast Iron shouldnt ever be dried out but should be stored with an antifreeze with LOTS of rust inhibitor in it. Normal engine temperatures will form ferrous oxide (black rust) which is a protective coating. Allow the engine to 'dry' and you form ferric rust (red rust) which is very harmful as its less dense than the cast iron and can develop extreme pressure when it forms ---- thus 'peels the onion' and produces the 'slabs'. If this blockage occurs, consider that slab rust has begun to form. Remove the manifold, invert it and with a stiff wire into the water passages go in and break up all the 'slabs'. To insure that the manifold hasnt developed 'pin holes' between the gas side and the water side (can drain back into the cylinders if pinholed - will destroy the cylinders) apply a pressure gage and a water line with a valve, block either the inlet or outlet, apply pressure, shut the valve and watch the gage. If the gage 'drifts' to zero then you have a pin hole (and also should see some water emit over time from the 'gas' side) and you then need a new manifold. How to check for blocked exhaust manifold, etc.: Run engine at near full cruising rpm. Take a bucket of known volume (gallons, etc.) to the exhaust outlet at the stern of the boat, with a stopwatch, etc. record the time that it takes to fill the bucket. Such an engine should have about 1 gallons per minute of cooling water coming out the stern outlet. ANYTHING blocking the cooling water loop will yield less than 1 gallon per minute. So if less than 1 gallon per minute, you have a blockage: slab rust in the exhaust manifold, broken pump impeller lodged in the line, coked water injection nozzle, junk sucked into the loop, etc. etc. etc. For most other engine in boat up to ~35 ft. the cooling water should be about 3 gallons per minute; the 5411 is called the 'pisser' due to its very low cooling water flow. The raw water cooled 5411 (and other raw water cooled engines) also forms carbonates inside the manifold which will eventually block the manifold and cooling water passages inside the engine .... either use a commercial boiler descaling compound (Marsolve or Rydlyme) OR take it off and to a 'radiator' shop and have it cleaned out by ultrasonic methods. Try NOT to use muriatic or hydrochloric acid to 'pickle' the salt out of the engine as they will also dissolve 'base' metal. Use muriatic or hydrochloric only if you cant find a decent boiler descaler. Carbonates are insolubles that 'drop out' from 'raw water' or seawater when its temperature is over 145 degrees F .... this is how 'rocks' are formed in nature. If your engine is 'raw water' cooled, then you should change the thermostat to one that fully opens at 135 degrees F. ... this will allow the cooling water to be UNDER the magic 145 degrees .... not perfect but will much lessen the 'salt' / carbonate build up. Dont ever drain the water to store a cast iron engine ... fill it with 50:50 antifreeze with lots of rust inhibiter to keep the ferrous (black/good/protective) rust intact. Good hunting.
One more thing to check
One easy thing to check is the air filter, since without adequate air flow, the engine won't operate at normal revs. I'd take the air filter completely off and see if the engine gets up to the revs it did last fall. If so, change or clean the filter.
One easy thing to check is the air filter, since without adequate air flow, the engine won't operate at normal revs. I'd take the air filter completely off and see if the engine gets up to the revs it did last fall. If so, change or clean the filter.
Thanks guys!
I have a lot of things to look into now. I will hopefully be able to figure it all out this weekend and let you know what it was. Thanks again -Rob
I have a lot of things to look into now. I will hopefully be able to figure it all out this weekend and let you know what it was. Thanks again -Rob
Help...its still a mystery
Today a friend and I took off the exhaust elbow and checked it over again. No blockage. Next we checked the thermostat. Stuck! I had a spare and replaced it. I still can't get the engine over 2000 rpm in gear. I even took out the thermostat and tried it without the thermostat. 2000 rpm max. No problem with the water pump feeling too hot anymore. When I throttle up it feels warm to the touch, not hot. I checked the water intake and am getting plenty of flow through the thru-hull. I checked the impellor - its fine. I changed both primary and secondary fuel filters. I bled the system everywhere it could possibly be bled of air. No difference. I changed the air filter - it looked like it was in very bad shape. No difference. I turned the shaft by hand - it seemed to turn freely. My last 2 ideas before I give up on this boat: 1. fuel - try fresh diesel with the feed line between the primary and secondary in a jerry can of fresh diesel. 2. replace the fuel pump (what are the odds this could be the problem???) Of course, I could just run the boat at 2 knots and forget about the whole thing! Help!!!!! Thanks -Rob
Today a friend and I took off the exhaust elbow and checked it over again. No blockage. Next we checked the thermostat. Stuck! I had a spare and replaced it. I still can't get the engine over 2000 rpm in gear. I even took out the thermostat and tried it without the thermostat. 2000 rpm max. No problem with the water pump feeling too hot anymore. When I throttle up it feels warm to the touch, not hot. I checked the water intake and am getting plenty of flow through the thru-hull. I checked the impellor - its fine. I changed both primary and secondary fuel filters. I bled the system everywhere it could possibly be bled of air. No difference. I changed the air filter - it looked like it was in very bad shape. No difference. I turned the shaft by hand - it seemed to turn freely. My last 2 ideas before I give up on this boat: 1. fuel - try fresh diesel with the feed line between the primary and secondary in a jerry can of fresh diesel. 2. replace the fuel pump (what are the odds this could be the problem???) Of course, I could just run the boat at 2 knots and forget about the whole thing! Help!!!!! Thanks -Rob
Last Shot
Morning Rob, sorry to hear that your still having problems. You didn't say, but what is the heat range on your engine now and is it still blowing steam, how many hours does it have?? If you can get 3 grand in neutral but only 2 in gear, obviously your linkage is ok. I would take a look at the governer to see how much it moves under load. The last suggestion that I would have it to check the compression on the engine. I don't want to sound scary, but it's possible that due to the hours and the heat problem, the cylinder walls could be galled or the rings siezed. If that is the case, the engine just doesn't have enough in it to get up to 3 under load. Sorry for the doom and gloom, but that's the last idea I have. Keep us advised!
Morning Rob, sorry to hear that your still having problems. You didn't say, but what is the heat range on your engine now and is it still blowing steam, how many hours does it have?? If you can get 3 grand in neutral but only 2 in gear, obviously your linkage is ok. I would take a look at the governer to see how much it moves under load. The last suggestion that I would have it to check the compression on the engine. I don't want to sound scary, but it's possible that due to the hours and the heat problem, the cylinder walls could be galled or the rings siezed. If that is the case, the engine just doesn't have enough in it to get up to 3 under load. Sorry for the doom and gloom, but that's the last idea I have. Keep us advised!
Try a different fuel supply
Move the fuel line from the tank and see if it runs better from a different tank temporarily. My old boat had a screen filter on the end of the pickup tube which had gotten blocked.
Move the fuel line from the tank and see if it runs better from a different tank temporarily. My old boat had a screen filter on the end of the pickup tube which had gotten blocked.
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