White smoke in Diesel

[daletournier]

See, this is how I know your a better mechanic than me...lol.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[a64pilot]

No, just years ago I got confused about Cetane and had to look it up.
Even Octane means different things or is measured differently, so you cannot compare 100 LL Octane airplane gas to 93 Octane car gas, the methods to determine Octane were different.
But your point is correct, Diesel can change chemical properties over time especially if contaminated with foreign substances like Bacteria and Algae and not be very good fuel, be harder to ignite etc, and have a different smell when it burns.
Ideally in this case I think he needs to have the fuel polished or replaced, new filters and have the injectors cleaned, need to have injectors cleaned every few years anyway, and if you don't know when they were last cleaned, have them cleaned anyway.
Out of four injectors on my old but 500 hour engine, I needed two tips replaced, I had all four replaced as they are not expensive and I wanted to start from a known point.
Often dirty injectors show up as just a knock, sort like a cold engine does, but the knock doesn't go away.

[Diesel Bill]

Originally Posted by a64pilot

Diesel is Cetane, Octane is completely different. They are actually almost opposite things, Octane is resistance to ignition, Cetane is how easily it ignites
Old fuel can cause problems of course.

My old brain is trying to remember many, many years ago cetane was derived from fish oil. Added to fuel oil to improve ignition quality.
Octane being the opposite, used to slow down the ignition burn in high compression gas engines. Now modern refineries have their own chemical formulas for both. On most gas pumps there's a label for octane. Research method plus motor method divided by 2. I guess this is supposed to say it's as good as the old Sunoco 260 from the old days. I think not!

[boatpoker]

Originally Posted by a64pilot

But your point is correct, Diesel can change chemical properties over time especially if contaminated with foreign substances like Bacteria and Algae

Algae simply cannot grow in diesel.

Water in diesel will separate, sink to the bottom of the tank and will not change any chemical properties of the diesel.

Bacteria grows only at the diesel water interface in the tank and does not change any of the properties of the diesel itself.

Diesel will degrade and lose cetane over time but I've run boats with 10yr old diesel without trouble and I've had trouble with 3yr old diesel but that was because of poor tank maintenance and infrequent filter changes.

[gamayun]

Originally Posted by boatpoker

Bacteria grows only at the diesel water interface in the tank and does not change any of the properties of the diesel itself.

Are you sure about this? I ask becaise bacteria use petroleum hydrocarbons as a source of energy in nature. Are biocide additives already in the diesel when we buy it?

[boatpoker]

Originally Posted by gamayun

Are you sure about this? I ask becaise bacteria use petroleum hydrocarbons as a source of energy in nature. Are biocide additives already in the diesel when we buy it?

Some diesel has biocides added and most have many other additives depending on refinery and brand as consumers we have no idea what they are.
There are uncounted types of bacteria and the type in this situation exists only at the interface.

[SeaSon]

Based on sludgy fuel described by the Original Post:
drain or pump the tank dry. Replace or clean fuel lines. Dispose of old fuel (only 27 gal tank).
Refill with fresh fuel, your ounce of biobar (I use biobar jf) , and change the filters.

Just do it right and move on.

[a64pilot]

Originally Posted by gamayun

Are you sure about this? I ask becaise bacteria use petroleum hydrocarbons as a source of energy in nature. Are biocide additives already in the diesel when we buy it?

"Bugs" will grow in both jet fuel and Diesel, it does take water though, but not water out of solution necessarily, water is in solution in all fuel. In Military Jet fuel we had to test the water content daily and often recirculate the fuel through filters with water absorbent in it, Polish the fuel if you will until water content was acceptable. This water in solution can come out of solution of course. Often the water you find in a tank came in the fuel, tiny amounts,not gallons of course.
Google Appl Jelly for an interesting read, years ago "bugs" were all in fuel, but only fuel that came through the Alberta Pipeline, hence Appl.
Valvtec fuel does contain a biocide, there are better biocides though.
I have run 30 yr old Diesel myself without issues, however the new ULSD is a different animal than old high sulphur Diesel, just as ethanol laced gasoline has different storage issues than old plain gas.

[Charlie]

Originally Posted by gamayun

It doesn't seem to me that water or sludge in the fuel would cause the smoke because wouldn't the engine NOT start at all? I don't mean to hijack your thread, but I'm curious about this issue, too, as I've been increasingly seeing more white smoke on start up. I recently read that running a diesel lightly can "crust up" (technical term, ya know) the injectors and cause this. Anyone know of this? Mine runs great after the initial plume (so I've also thought it might be unburnt carbon) and it doesn't do it when starting up on a warm engine.

I did a lot of research on this. If the white smoke rises. Most likel cause is steam. If the white smoke falls most likely cause is unburnt fuel.

If the smoke goes away after running for a little while it is likely unburnt fuel and as the cylinders warm up they burn the fuel more completely.

If the heat exchanger is partially clogged then there may not be enough water going through the system to fully cool the exhaust. This creates steam.

I am not a licensed mechanic. Just a man who had a problem a mechanic could not fix.

Solution. Clean heat exchanger tubes and inspect entire water system.

Have injectors serviced. Less exensive to have this done at a tractor dealer such as Allen Diesel Energy in Yuba city. Four yanmar injectors rebuilt for around $100

Have injectors serviced

[dennismenace111]

White smoke is usually oil burning... black smoke is usually fuel.

[a64pilot]

Originally Posted by dennismenace111

White smoke is usually oil burning... black smoke is usually fuel.

Oil is usually blueish in color, and the smell is unmistakable.
Black smoke is partially burned fuel, there was enough heat to get the fire going, but not enough oxygen to combust it completely. Fuel white smoke is fuel vapor, there wasn't enough heat to get it going.

[F10]

I have an old Mitsubishi gasoline pickup (I think your vetus is also a Misubishi block). On start up I get an antifreeze type smell with white smoke. Clears up within 15 seconds. I also loose anti-freeze coolant with no apparent leaks. I think I have a small head gasket leak. When I shut off a hot engine the cooling cylinder at times (if valves are closed) draws in antifreeze through the leaking head gasket. On starting the coolant in the cylinder burn off within 15 seconds (sometimes it sounds like running on three cylinders for this time). Once the engine heats up the head gasket leak seals due to expansion. Engine runs fine there after. I imagine I have a very small leak. I would try to replace the head gasket, but the truck has run this way for 10 years so a little afraid the repair might do more damage by opening up the engine- truck is 30 years old and about at end of life due to rust...so I'll just keep running her and let old dogs lay...

Are you losing any coolant over time?

[Diesel Bill]

Originally Posted by a64pilot

Oil is usually blueish in color, and the smell is unmistakable.
Black smoke is partially burned fuel, there was enough heat to get the fire going, but not enough oxygen to combust it completely. Fuel white smoke is fuel vapor, there wasn't enough heat to get it going.

I tried to post on this when it was new. Server was acting up and wouldn't let me post. So here's my 2 pennies.
By the way everyone got in ahead of me on this but a64pilot is absolutely correct.:thumb
White smoke is unburned fuel vapor caused by cold liners, low compression.
Grey/gray smoke is burning oil, and black smoke is to much fuel and not enough air like over fueling before turbo builds boost or overload I.E. to much prop.
Anyone ever hear of the old International DV 550? Was designed to idle on 4 cylinders and run on 8. At start up they put out so much white smoke the entire area would disappear for 5-10 minutes.

[Caolan]

Just an update to all. I used BioClean6, replaced fuel filters and the white smoke and smell has all but disappeared. I figure it is now just an issue with residue still in the tank.

Thank you all for your suggestions and information. There was a lot to consider and I am elated that it was the quick fix that resolved it.