White Smoke and we already have a Pope

[Charlie]

Hi All:

I have a Yanmar 4JH4E. It has approximately 1000 hours. After tieing up to the buoys at Angel Island in SF Bay we awoke to a no wind situation. Thought I would take the oppurtunity and motor up to the GG Bridge and sail back in when the wind built. We got to the top of the island and I noticed white smoke coming out of the exhaust. Shut the engine down. With the engine idling no problem. At around 1700 and then up to our cruising rpm of 2100 the smoke spewed out. With no wind we motored back at around 1200 RPM. Got to the dock tied the boat up real tight and tried to get the smoke to come out. Revved it up to 2500rpm's for a couple minutes and no smoke. In neutral or in gear no smoke. Took it out on the water and there was smoke. The only difference that I could see is that my boat tends to squat at 2000 rpms. The stern sinks a bit. So I checked the mixing elbow. Clean as a whistle. I then revved the engine up to 1500 rpms and released the injector nuts (probably the wrong term). cylinder 1 no change. Cylinders 2-4 you could hear the difference. Took the injectors out and brought them to a shop for testing. 1 was sticking slightly and 4 was perfect.

They are going to clean the injectors and then I'm going to reinstall the injectors but what is my next step should this not resolve the problem. I guess I could do a cylinder leak down test but not sure I have the correct fitting. Any other thoughts?

[model 10]

You need to be clear if it is white or gray. White is water and gray is fuel. You can smell gray smoke.

[Charlie]

The smoke is definitely white. It did not smell sweet.

[delmarrey]

Hi Charlie,
When the boat is underway (squatting), is the exhaust outlet going underwater causing back pressure?

If you are getting water in your exhaust header you might want to check/pull the heat exchanger. They are aluminum and do have some corrosion problems, especially if sitting with saltwater in them.

BTW motoring while tied to a dock does not give a true representation of being underway. The prop begins to cavitate, not really putting a load on the motor as if underway. It's just recirculating most of the same water in a circle around the prop.

[delmarrey]

Also check your cooling water level. If it's sucking out coolant then it could be the heat exchanger or head gasket.

[Get-away]

I'd say thats steam, fresh water cooling system is adequate if your temps aren't going up but reduced raw flow perhaps is allowing raw water to vaporize in the mixing elbow creating the white steam you are seeing. Check for a clogged sea-strainer first and if thats ruled out check water impeller and vanes.

[bongo]

White can be either steam or smoke. If it is steam it dissipates quickly and does not linger. If it is white smoke the older textbooks say that it is burning too lean. Black is too rich. What we look for in the industry is almost clear to light brown, "economy haze". Of course, I'm talking about much bigger diesels, but, a diesel is a diesel.

[warmbluewater]

My Taswell is powered by a 4LH-TE. I had a similar issue last year. For me the white smoke was water vapor. It dissipated quickly after leaving the exhaust.

For me the solution was replacing the raw water impeller. I guess the raw water flow through my heat exchanger was low and it would actually boil off a little prior to discharge. It worked!

Big question is white vapor or white smoke. Very different issues.

Cheers!

[svthreecheers]

Hi Charlie
Are you getting your full power ? Sometimes with partly plugged fuel filters the
engine will smoke white under load.
You also said that when you opened up the High Pressure fuel line on injector # 1
while the engine was running you could not hear a differance in RPM.That would
indicate that this cylinder is not firing proper.If repairing the Injector does not cure
the problem check the Compression ( on all cylinders ).It mite be low on #1
Cheers
Siggi

[Charlie]

@ Guy It is white.
@ Del:Thanks I will check the coolant and the heat exchanger
@Getaway Water seems to be a consistent theme here
@ Bongo I put my hand in front of the smoke and did not get a sooty feel. Leads me to believe it is water.
@ WBWater Thank you that is something easy to inspect.
@ SV 3cheers Thanks for the ideas I will check that as well. Yes I am getting full power but now that I said that I can't believe that is true because one of the cylinders was not firing properly. I have a dual racor system with a pressure gauge and it says that there is no undo pressure.

The gentleman at the injector shop told me that it could be a problem with the low pressure pump not bringing enough fuel up and then the governor of the injection pump sending out too much fuel. I did not understand his theory but he said to look for a lack of fuel problem which could be the case with a partially clogged fuel filter. I should change the filter as wells as these other inspections.

[delmarrey]

Out of all these I suspect the flow of raw water thru the exhaust elbow as the culprit.

Maybe the intake while underway? It's all a guess. A process of elimination.

[parado]

it may be you are burning an excessive amount of oil- loose oil control rings rattling in the bores. Oil burns with a white smoke and would not smell good, like you experienced. My race car would do this if my timing was just a little off, a huge amount of white smoke, I could not see behind me, and no, it wasn't tire smoke, I could hear the motor pinging. You could do a leak down test on each cylinder, but may not catch an oil control ring problem.

[seabreez]

Originally Posted by Guy

You need to be clear if it is white or gray. White is water and gray is fuel. You can smell gray smoke.

White smoke is water vapour, blue is oil, black is excess fuel or choke is "on" (gasoline engines) White smoke is overheating engine or lack of water flow and not cooling down your exhaust gases enough in the exhaust manifold. I would go directly to the intake water pump and check the impeller...

[Greg H]

Friend had the same problem with his yanmar. Turned out the diaphragm in the lift pump was split and putting fuel into the crank case. While at the dock no problem. As soon as the boat was in even slightly rough water white smoke. Yes white smoke. Check to see if your oil level is higher than it should be. If so fuel is going into your crank case and as the level rises and the boat is bouncing around fuel/oil is splashing onto the cylinder walls then going past the rings. If that's the case replace the pump change oil several times.

[delmarrey]

Originally Posted by Greg H

Friend had the same problem with his yanmar. Turned out the diaphragm in the lift pump was split and putting fuel into the crank case. While at the dock no problem. As soon as the boat was in even slightly rough water white smoke. Yes white smoke. Check to see if your oil level is higher than it should be. If so fuel is going into your crank case and as the level rises and the boat is bouncing around fuel/oil is splashing onto the cylinder walls then going past the rings. If that's the case replace the pump change oil several times.

If so, that can also cause a run away motor.