White exhaust smoke?

wetass · Mar 19, 2012

Is there any water (not steam) that is passing through - couldn't tell if it was belching water as well? Should be a healthy amount of water spitting out of there as well.

robertsapp · Mar 19, 2012

You asked for thoughts:

Is the engine difficult to start? Does it run smoothly? When you run the engine in the slip, do you see an oil sheen on the water? Does the smoke linger, or does it quickly dissipate? Have you noticed any increase in coolant consumption?

I believe that generally, white smoke is either steam or unburnt fuel. If it's steam, it will dissapate quickly and not leave an oil sheen on the water. Likely sources are a head gasket failure, which would result in increased coolant consumption, or a problem with your seawater flow and cooling, which could be anything from a plugged suction screen, missing impeller vanes, clogged heat exchanger or a partially plugged mixing elbow, or anything in between.

Unburnt fuel should make a white smoke cloud that lingers and leaves a fuel sheen on the surface of the water. Possible causes are loss of compression in a cylinder or a bad injector, among others. These could produce hard starting or rough running.

That's where I'd start.

robertsapp · Mar 19, 2012

Oh, and to answer your original question, yes, you should be concerned about it. Properly running diesels do not do this. Yours is trying to tell you something.

Bill Roosa · Mar 19, 2012

This is the same stuff that comes out of your car tail pipe on a cool morning.
We get this "panic" posting EVERY Fall and spring.
The "white smoke" is clearly dissipating as it moves from the boat.
I suspect that if you look down wind you will not see the cloud much further than a boat length and then it disappears. This is just water vapor and is not a problem.

Now if you looked down wind and you saw a persistent smoke that just hung in the air till it was so far away it got lost in the haze you would have true white smoke. It also smells of diesel much more than normal exhaust.

To confirm beyond what I explained above note the air temp. If you never see it on hot dry days and only see it on cool damp ones that is clearly not an engine problem. Also, try running the engine during the heat of the day and note the results.

kpgraci · Mar 19, 2012

I don't know much about diesel engine smoke but I thought the inclusion of the video to show the problem was brilliant. If a picture is worth a thousand words, what is a moving picture worth?

Benny17441 · Mar 19, 2012

White smoke is water, bluish is oil and black is fuel. Is the engine running hotter? Check impeller, hoses, coolant level, belts and raw water flow.

mghunter310 · Mar 20, 2012

Check your diesel filter / water separator for water in your diesel.

A full metal tank will not get water condensation whereas a halfl full one will generally build up water from condensation within the tank itself.

Bill Roosa · Mar 20, 2012

I would note Scpharby that all the folks that are saying you have a problem are from southern climes. They probably have never seen "tailpipe smoke" from their cars either.
FWIW

robertsapp · Mar 20, 2012

Bill Roosa said:
I would note Scpharby that all the folks that are saying you have a problem are from southern climes. They probably have never seen "tailpipe smoke" from their cars either.
FWIW

True. If I saw that much smoke from my exhaust here in Florida I'd think my engine was on fire.

Having said that, if the problem is indeed just condensation, that should be very easy to determine, as the "smoke" should completely disappear when it warms up in the afternoon. Yes?

Bill Roosa · Mar 20, 2012

That is correct robetsapp
After being on this board for a few years you start to see patterns. With the first chill of fall and early on in spring we get "white smoke" posts. Kinda like the "hunter starter solenoid problem" and others.

jtm · Mar 20, 2012

One more thing to check>
Make sure that your compression levers are fully engaged! If you or someone was recently in the engine box and a sleeve got caught on a lever, or you backed off the compression lever to lube the cyl before engaging the lever & starting for the first time this season, you may not have them fully engaged and "Clicked" into position-
check that!

Benny17441 · Mar 20, 2012

We all know what engine exhaust from condensation looks like and it clears up as soon as the engine expells the humidity from the system. Prolongued water vapor emmission points to flow problems in the cooling system.

Herman18887 · Mar 21, 2012

I have the 3ym30 on my 2005 Hunter 33. I'm no expert, but the last time I saw white smoke was after I cleaned my raw water strainer and did not tighten it well. As other people have suggested, the white smoke could very likely be caused by a problem with the seawater cooling flow.

Robert 47 · Mar 22, 2012

Bill is trying to tell you what the problem is. If the smoke stays, you have a problem. If it goes away, it is steam. No problem. Very simple to understand. Weather... Now if you get it all the time you have water in your combustion chambers which is leaking in from the head gasket. If this is not corrected, the water will drain on down past the cyclinder rings and settle in the oil. Now you have a real problem. Check your oil to see if it is "milky". If it is over the full mark and you have not added any oil to the crank case, you have water in your oil. These are worse case sonarios. Good luck.

Tally Ho · Mar 23, 2012

My H280 exhaust exits under the boat. Would steam or smoke be visible (if there was a problem that smoke would be a sign of)?

I came into my slip a bit too fast once last year and hit the throttle pretty hard in reverse, and there was some white-ish smoke behind my stern. I doubt that was condensation (I am in the Chicago area, but this was in the heat of the summer).

I will be putting the boat in the water in a few weeks, any special engine prep recommended before it is in the sling and splashed?

Greg