Engine smoke and injectors

Hello,

I posted some of this in the Classifieds section asking for a source for new injectors. But, here is my problem.

Our engine produces more white smoke than I think it should and we'd like to remedy that. It is not blue smoke, does not use oil and does not smell like oil. It has a lilttle hint of diesel smell to the smoke which leads me to think it is an injector issue. But, I AM NOT AN ENGINE GURU. Everthing I have read, Calder, Compton and others, points me towards injectors.

The first time we noticed the excess smoke was on our trip to Desolation Sounds. We left Lund one morning and just a little ways north of the harbor our friends radioed us saying we were blowing a lot of smoke. We backed off on the throttle to 1800 rpm's, we were running at 2000 rpm's normally. The smoke diminished some but still excessive. Temperature was normal so we pulled into the Copeland Islands and dropped anchor to check it out. I got in the dingy and examined the exhaust for smell and color. Whitish smoke, a little diesel smell but no oil smell. We shut her down, checked all fluids and talked about it with our friends for 15-20 minutes. Started it back up and the smoke had diminished considerably. I figured if it was still heavy smoke we'd just go back to Lund, but it wasn't, so we continued North. From that point on there was no heavy smoke issue. 400 miles later we are back home in La Conner and put her up for the winter. Fast forward to spring and the Willard rendevous. Smoke again. Time to address the issue.

Not only is it embarrassing, it is a symptom that something is amiss. Researching the issue through various forums and books points me to the injectors. I'm trying to solve it myself before having to go to a mechanic. Not pinching pennies, just want to learn more about the engine and how to diagnose and cure any ailments as if I were out cruising away from any help.

Any thoughts? Am I on the right track? I'm thinking we'll get new injectors and have our old ones rebuilt to carry as spares.

Thanks for any feedback,

not to insult your intelligence....your exhaust is ALWAYS gonna smell like diesel...

sure the white smoke isn't just water vapor? some days it can be scary thick and others just a wisp. could be injectors or a bit of coolant getting to the cylinders....often it's just how the cooling water interacts with the exhaust and a bit of vapor is created...again scary but not abnormal.

here's another experienced person's opinion that I agree with...

Diesels do smoke—and if you have to have a small amount of smoke, white to very pale gray that dissipates quickly is good. This small amount of smoke without much color indicates a healthy burn ratio of air and fuel and that there are no problems with fuel metering or oil burning.
Vast quantities of white smoke, especially under a high load when the engine is hot, can be another story. White smoke can actually be steam. This problem usually would not be indicative of water in the fuel, since that much water mixed in the diesel fuel would cause starting and running problems. However, a small water passage from the coolant side into the combustion chamber would allow the engine to start and run properly, especially when cold, but to issue steam as it warms up.

Engine smoke

psneeld,

No problem questioning the intelligence here, I am not an expert. I am aware that the exhaust should have a diesel smell to a point. I also have a diesel pickup. I was trying to accutrately report what I found on examination. I appreciate the feedback and considered the excessive smoke as a possible temp issue, but that did not seem to be the case. The smoke did not dissipate rapidly when we left Lund or left the dock at La Conner. That is my concern. I expect some smoke from a 1977 engine, but would like to minimize it as much as possible and ensure it is running optimally. She starts very easily and idles smoothly, even after a long winter layup.

kolive said:

psneeld,

No problem questioning the intelligence here, I am not an expert. I am aware that the exhaust should have a diesel smell to a point. I also have a diesel pickup. I was trying to accutrately report what I found on examination. I appreciate the feedback and considered the excessive smoke as a possible temp issue, but that did not seem to be the case. The smoke did not dissipate rapidly when we left Lund or left the dock at La Conner. That is my concern. I expect some smoke from a 1977 engine, but would like to minimize it as much as possible and ensure it is running optimally. She starts very easily and idles smoothly, even after a long winter layup.

Click to expand...

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Sounds more like water vapor or even some steam. Are you sure your exhaust water has proper flow? I had an exhaust manifold going at one point, looked fine on the outside, was weeping a small amount of water into the exhaust near the elbow and created a white smoke appearance at times. It seemed to come and go at times.

Are you seeing an oil sheen on the water behind your exhaust outlet. Bad injectors pumping excess oil into the jugs will be mixed with the exhaust water and float on the water surface behind the boat.
Larry B

kolive said:

psneeld,

No problem questioning the intelligence here, I am not an expert. I am aware that the exhaust should have a diesel smell to a point. I also have a diesel pickup. I was trying to accutrately report what I found on examination. I appreciate the feedback and considered the excessive smoke as a possible temp issue, but that did not seem to be the case. The smoke did not dissipate rapidly when we left Lund or left the dock at La Conner. That is my concern. I expect some smoke from a 1977 engine, but would like to minimize it as much as possible and ensure it is running optimally. She starts very easily and idles smoothly, even after a long winter layup.

Click to expand...

Do you have a 120hp Lehman? It looks as though you may have excessive soot build up in your engine. Your boat is a 30' trawler? Tell us a little more about your boat and your engine.

My 80hp Lehman smokes at start up and will smoke until I get it up to temp. My Dad's 120hp Lehman does the same thing. In fact, when behind him in calm winds, his engine will smoke quite a lot and stick around like a tail. It stops when it gets up to temp..... it's been that way for YEARS and the engine has never let him down.

It's good that you are concerened and trying to nip something in the butt before it gets worse. Just be careful that you aren't chasing something. 30 year old Lehman diesels smoke and never have been worked hard enough for what they were intended/designed for (Tractors).

Being a boatdiesel follower for many years, injectors are usually one of the last things to look at when diagnosing smoke or performace issues.

Engine Smoke

As requested, our boat is 1977 Willard 30/4 FS with a Perkins 4-108 50hp engine.

I will check out boatdiesel forums and see what they have to say. The books I referenced include Nigel Calder and Peter Compton and clogged or malfunctionoing injectors appears high on the list of potential issues, which is what I drew upon to ask my questions. I am keeping open to the forum to provide some personal insight as well.

Thanks for everyone's reply.

I agree that the injectors are one of the last things to look at. If you really have white smoke from injectors usually when the exhaust is sniffed there will be a STRONG grab your nose smell.

You likely have steaming. That can be atmospheric conditions and as suggested can be very light to much heavier .

If the white is heavy consistently that can be an indicator that your cooling system is on the point of giving trouble. Usually the raw water flow is getting restricted. There is still enough water to cool the engine but it is getting too warm, the volume is down and when injected into the exhaust stream no longer cools the gasses enough and steams readily.

Can be the raw water pump getting worn or the impeller weak or missing
vanes, clogs from barnacles or such in the pickup, air leaks on the suction side of the R.W. pump, hoses delaminating or collapsing, clogging gear cooler, exhaust riser clogging at the shower holes or the injection nipple where the raw water enters from the heat exchanger.

If impeller vanes are missing then not only will that reduce pumping action but the pieces will partly block the heat exchanger reducing water flow.

A flow meter can be used to check water volume. Pressure and vacuum guages can help to test for high pressures or vacuum.

I asked a respected diesel mechanic to check to see if my injectors were causing the slight smoke when I first bought my boat. With the engine running, he loosened the injectors one at a time to see if the smoke diminished. It did not.

The conclusion was that there were no defective injectors. Of course, it's possible that they are all slightly worn, but there was no "defective" injector causing the smoke.

That's a test you might try.

Injectors

Thanks for the input and ideas of what to check along with the injectors. I go back to the boat June 18th to bottom paint and will go through the checklist and see what I find.

1. Check and replace impellar.
2. examine raw water cooling and heat exchanger.
3. loosen injectors, with a "real mechanic prsent".
4. check Racor for water
5. Sand and paint the bottom
6. Apply wine-esthesia in the evenings to recover from chores.

If your engine temp is fine, your oil pressure is fine, the engine is running smoothly throughout its rpm band from idle to cruise rpm, the engine starts fine, the oil and coolant levels are fine, the water flow out the exhaust is fine, it starts becoming difficult to say there is actually a problem. At least a problem with the engine.

Our FL120s put put out steam in the exhaust during the winter, none in the summer. In fall and spring it depends on the day's temperature and humidity. Sometimes there's none, sometimes there's some.

You say "you left Lund one morning." Cold morning? High humidity? Then as the day went on the "smoke" went away. Day get warmer? Humidity drop?

And now in the spring it's doing it again? Cold days? Higher humidity?

If I read your first post correctly, you've got some "white stuff" in your exhaust but no problem whatsoever with your engine. An injector going squirrely on you is going to affect the running of the engine. Not as smooth as usual, perhaps some sooty smoke from improper combustion in a cylinder, etc. Maybe a little harder to start.

A pump impeller loosing its "compression" due to wear plate wear, cover plate wear, weak blades, broken blades, etc. can put less water through the system. But you'd see that as maybe a little higher running temperature, a little less waterflow out the exhaust, a transmission that's running (by feel) a little hotter than normal.

By no means take anything you read on an internet forum seriously. Or at least don't act on it without getting professional advice first, particularly when it comes to engines, propane, and electricity. So if you're really worried about it I'd hightail it down to whatever diesel shop you use and trust and who are familiar with your type of engine and tell them what's going on. Maybe something really does need some adjusting or cleaning or tweaking. I don't know.

But based on what you've said so far, I don't see an actual engine problem here because your engine's not doing anything wrong.

Maybe there's something going on inside your exhaust system. After all you are injecting salt water into it (I assume) so if something is leaking into something it's not supposed to get into in your lift muffler or water-cooled elbow, perhaps it's causing more steam than is "normal." Again, something for the diesel shop to check out.

When we bought our boat one exhaust put out more steam than the other one in the winter. Diesel shop said don't worry about it, and since just about every other boat we saw on the water during the winter was putting out various amounts of steam in their exhausts, we didn't (worry about it).

Then we had all-new exhaust systems fabricated and installed on the boat. New water-cooled elbows, custom-made fiberglass lift mufflers, a whole new exhaust configuration from the exhaust manifolds to the mufflers with everything running downhill to completely eliminate any possibility of water getting back into a cylinder.

And guess what? That winter, the exhausts switched roles. One still put out more steam than the other one, but it was the one that had put out less steam before. Mentioned it one day to the owner of our diesel shop that had installed the new systems. His scientific diagnosis? "It happens. Go figure."

That was some ten or eleven years ago. Other than routine servicing, the engines, injectors, etc. have never been touched and they run exactly the same as they did the day we bought the boat.

So don't go chasing problems that aren't there. Get a professional diagnosis first.

White smoke article

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