Exhaust Steam

Sep 29, 2021
5
Bristol 41.1 Little River SC
Just bought our 1981 Bristol 41 center cockpit. When we are motoring we get white steam/smoke coming out back exhaust. Our temp runs from 160-180 which doesn't seem that bad. Should I be concerned? Or is it just a long exhaust from the engine and I just need to ignore it?
 
Nov 8, 2007
1,397
Hunter 27_75-84 Sandusky Harbor Marina, Ohio
Sounds like it could be a head gasket. White exhaust was what made me call the diesel mechanic, then charter another boat while we waited for him to work through his backlog and repair it.
 
Feb 21, 2013
3,794
Hunter 46 Point Richmond, CA
Welcome to the forum and congratulations on your new sailboat!!

As long as you have good water flow out the exhaust, engine temps are normal and the exhaust has steam only you are probably OK. Do an internet search on steam in the exhaust and you will see many threads on this subject and other potential causes.
 
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Jan 4, 2006
3,912
Hunter 310 West Vancouver, B.C.
Any chance you may be looking at blue smoke ? If it disappears quickly, it's most likely steam. If it slowly disappears, smoke.

See if you can wrap your had around anything metallic after the heat EX discharge mixes with the exhaust gasses. Hot or cold ? If cool, forget it and chalk it up to one of the mysteries of the universe.
 
Dec 25, 2000
5,049
Hunter Passage 42 Shelter Bay, WA
Or is it just a long exhaust from the engine and I just need to ignore it?
Different engine here, but our 1991 Yanmar runs smoke/steam free. However, there was a time when I failed to properly replace the sea water strainer cover after cleaning, which allowed a reduced water flow. That was when I noticed steam coming out the exhaust, but engine temp was ok. Reset the cover and the exhaust returned to normal operation.
 
Feb 21, 2013
3,794
Hunter 46 Point Richmond, CA
blackjacksparrow..........if you have good flow out the exhaust one possible cause of steam in the exhaust is fouled mixing elbow and needs to be cleaned.
 
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Jan 4, 2006
3,912
Hunter 310 West Vancouver, B.C.
if you have good flow out the exhaust one possible cause of steam in the exhaust is fouled mixing elbow and needs to be cleaned.
@sail sfbay , can you please add some detail to that idea.

I've always thought that unless the discharge water is 100 C. (212 F), any steam in that fast moving froth of sea water and combustion products is going to be condensed way back up the line in the blink of an eye.
 
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Feb 21, 2013
3,794
Hunter 46 Point Richmond, CA
Just a therory............if the hot exhaust gas and water are not fully mixed due to insufficient contact time or poor contact then they might achieve equilibrium. I have seen this in the oil refining industry when mixing two streams with different distillations and temperatures, which required a custom-designed static mixer to achieve thermodynamic equilibrium. My 2005 sailboat does not have steam in the exhaust and good water flow but my 1984 powerboat does have some steam, even with good water flow so my only explaination for the the latter is it is time to clean the or replace the mixing elbow.
 
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WayneH

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Jan 22, 2008
866
Tartan 37 Pensacola Shipyard, FL
White smoke can also be from an improperly timed injection pump. I had my injection pump overhauled and I reinstalled it to the scribe marks I made before removing it. My Westerbeast 50 started right up but was smoking on start up and would not go away. Mechanic said the timing was off so we adjusted the pump, started the engine, observed the discharge, shut it down and repeated until we found the new position for the injection pump. It was not much of a rotation of the pump but the difficulty was working against the injection lines. And right this second, I can not remember if we advanced or retarded the pump.
 
Oct 26, 2008
5,021
Catalina 320 Barnegat, NJ
Earlier this summer, I had some white steam in the exhaust when I ran RPM's up a notch above our normal level. Actually, I could hear the change in tone of the exhaust before I actually looked to see what was going on. Throttled down and it disappeared. Back at the dock, I checked the strainer at the raw water feed and found it partially blocked with grass. No issues appeared thereafter. If you are seeing steam when running in 80 degree temp, your engine is telling you something. Listen to the tone and you may also detect a difference. I suggest that you look for partial raw water blockage as others have also suggested. Look for the simple solutions first! :cool: