All of a sudden, dark gray smoke and reduced rpm. ??

Finally ready to go snapper fishing. Loaded up with 5 souls on board, 4 ice chests, full fuel, 15 fishing poles, food, etc and headed for the Gulf. 3 hours later after running at 15 knots with the 34Californian LRC and twin 3208sNA we are out 12 miles in the Gulf and the starboard engine has loss of rpm and is putting out dark gray smoke. RPM now 2000. Been running 2400rpm and the water temps 178 degress or so.

Throttle back and I go down to get into the engine room from under the ladder and when I open the door engine room is full of smoke and I see smoke and water pouring out of the other engine's inboard riser at the 90 degree elbow connection. Brand new 90 degree 5 inch rubber elbow which connects exhaust system to that riser has split. I note this because it may be germain to the other engine problem, that is maybe exhaust smoke from port engine has clogged air filter on starboard engine.

What can cause engine to suddenly lose rpm and start producing dark grey smoke. Not blue, not white, although there is a little white while running which I conclude is steam since it disapaites rapidly. Temps holding steady at about 178 degrees for the whole time.

What is grey smoke as compared to blue smoke? A fuel filter clogging up would cause a reduction in rpm but would it also casue smoke? I will change air fliters just in case that is problem but where do I go from there? Hire a mechanic??

We ran home on that engine only, at 2000 rpm, a little grey smoke and 7 knots. 6 and 1/2 hours. Didn't have an elbow on board to fix the other engine, although we did patch it up with a rubber sleeve, emergency tape and duct tape just in case. Aw the joys of boating.

Well, I checked the air fliter, it was toast so to speak. Replaced it and turned to 2400rpm at the dock and no smoke. Of course when I get a load on it it may be a different story.

No load RPM's tell you nothing.
Blue smoke = lube oil
White smoke = water
Black smoke = fuel

I am sooo not an expert, but since no one else has chimed in...maybe somehow coolant in a cyl?

Grey exhaust can also mean a blown head gasket.

Go to boatdiesel.com

You can check out Tony's tips on sbmar.com or post your issues on boatdiesel.com. I think the answer will be easily found.

Timjet, thanks for the suggestion. As a member of boatdiesel.com I am familiar with Tony's good work. I searched all the articles there, which included his, and found one on white smoke by Tony, but nothing else.

I also searched Tony's tips at Seaboard and didn't find anything there. Maybe I missed it somehow, but do you know of a specific article or tip that addresses gray smoke? If so would appreciate some links to get me there. Thanks

Fighter Pilot,
Though the following article does not specifically address the smoke issue you are experience it may be helpful in analyzing the problem.
Seaboard Marine - Tony's Tips | Understanding Low Power Troubleshooting

You've probably read it, but if not it may be of help.

I would not hesitate to call Tony directly, I have several times.

Why don't you talk to a diesel shop? They're the ones whose livelihood depends on their knowing about engines. Asking an amateur Internet forum to offer suggestions as to the cause of an engine problem like "gray smoke" is a bit like asking a guy flying a kite to tell you why your airplane's behaving badly.

Instead of getting a bunch of speculation, if the shop is a good one you'll most likely get the correct answer to your question, the solution to your problem, and the ability to fix it. Sure, you'll have to pay for it but when it comes to advice, troubleshooting, and repair the value of what you get is generally related to what you pay for it.

Marin

Yes, there are lots of good shops to regarding 3208s. But as you well know, this is the age of sharing our every thought on some sort of forum or social network. You may have seen the Facebook article last week about the young girl in Australia who was helping her grandparents count their life savings on the couch and she posted a picture of the loot on Facebook, an hour or two later the robbers showed up.

My question is why a why a rubber elbow before the riser? The issue for pilot is two fold, fix the engine and insure proper design on the exhaust riser and mixer system.

Marin said:

Why don't you talk to a diesel shop? They're the ones whose livelihood depends on their knowing about engines. Asking an amateur Internet forum to offer suggestions as to the cause of an engine problem like "gray smoke" is a bit like asking a guy flying a kite to tell you why your airplane's behaving badly.

Instead of getting a bunch of speculation, if the shop is a good one you'll most likely get the correct answer to your question, the solution to your problem, and the ability to fix it. Sure, you'll have to pay for it but when it comes to advice, troubleshooting, and repair the value of what you get is generally related to what you pay for it.

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What if the fix was as simple as fishing line in the prop or a poorly fitting hose clamp and someone here had conquered the same problem? And if we always went to a pro with our problems, there'd be no need for your expertise here or even this forum...isn't that why we hang out here, to talk about our boats with fellow boaters?

I would say ask anybody and everybody from the diesel mechanic to people on any internet forum.
Knowledg is what you are seeking.
Advise is something you can always ask for .You don't have to take it.

If you ever have this problem again you will know what to do rather than call a tow boat.

I rebuilt the top end of my 3208. Never did it before but man did I learn a lot about the components of my boat and motor.
If you break down on the water you have got to be able to effect repair.

If it can't be repaired maybe it shouldn't be on the boat.

SSD

I believe in asking questions on any number of forums. I have had great responses with valuable information by doing this. Someone with first hand experience adds to the pro's knowledge. I find even the experts are lacking in knowledge if the subject matter is from an older engine. For example, the 3208 has a couple of local mechanics in the area and I have talked with them but their guidance is not any better than what I have received from this forum and boatdiesel.com.

Boatdiesel.com has two of the formost experts in marine engines that moderate their site and offer to share their knowledge from years of experience working with diesels. Amateur sites such as this one has people with realtime happening to them experience as well.

If thru the forums I can't get a handle on the problem than it is time to step up and pay up, but why pay $150.00 to have a mechanic drive out and tell me to change the air filter as a start? A forum expert suggested that and that has been done. At no load high rpm it looks good. Time will tell with load on the engine.

The rubber elbow situation did go to an expert. He is going to clean the riser and see what we have. I have been looking for a souce for the riser without any luck with the thinking, really ought to replace it. As to the efficacy of the design-it may be lacking, but that is the way the V-8 engines were put in many boats, expecially the Naturals where the temps. don't get too high. A wet exhaust, rubber elbow good to 250 degrees was used for the inboard riser to exhaust pipe hook up, after the riser, not before it. This one worked OK for 30 years until the riser got plugged up.

Should find out condition of the riser late this afternoon or tomorrow and than decide what to do. Local Cat. Dealer is big but doesn't work boats. Risers are boat type things, so may be out of luck there. Searched Barr and Osco but didn't find any Cat. risers. Will keep searching just in case existing riser is a lost cause. Thaks for the suggestions.

N.C. Machinery in Seattle deals in Marine.
A good guy to talk to is Jay Hederson. I don't know how far from Seattle you are but there is always shipping. 1-800-562-4735.
SD

I'm a long way from Seattle. In the panhandle of Florida, but thank you for the contact.

Did the new air filter fix the problem ? Is it a paper filter ? .. did it get wet when you had that wet exhaust leak ?..or even damp?

Don't think it really got wet. We ran that engine 7 hours after we had shut down the engine with the leaking elbow, so if it did get wet it was dry the next day when I got around to checking it. It is a round, paper filter., shaped like the old style you would see on the old auto gasoline engne. I did turn up the engine to 2400rpm while at the dock and didn't get any smoke. Won't know for sure until we take the boat out again and get the engine under load, but if you could have seen the filter there wouldn't be any doubt in you mind but what it had severely reduced the possible air flow.

When we first aquired the boat there was discussion about putting on K and N type fliters, but a couple of experts suggested we save our money since the standard filters used are compeletly adequate in the water/no dust environment. The paper would probably rot away before the filter would clog up. But, on an earlier trip we had a rear fresh water hose blow off and the engine and the filter from the looks of it got hot. That coupled with the recent smoke really did a number on it. I am going to check the other on next time at the boat.

jeffnick said:

What if the fix was as simple as fishing line in the prop or a poorly fitting hose clamp and someone here had conquered the same problem? And if we always went to a pro with our problems, there'd be no need for your expertise here or even this forum...isn't that why we hang out here, to talk about our boats with fellow boaters?

Click to expand...

Useful fly stuff, as Eric likes to call it, can often be gotten from Internet forums. But for important stuff, I regard asking a bunch of amateurs on an Internet forum to be a complete waste of time which is why I never do it.

As SD says, you don't have to take advice. But based on much of what I read on boating and aviation forums most of the advice on things that are actually important is more often than not inaccurate or incomplete at best and downright wrong at worst. Which is why I don't waste time looking for important solutions on forums like this one. Instead of wading through a bunch of speculation from people with totally unknown credentials I can make one phone call and solve the problem.

Forums like this one are very entertaining in a sort of mindless pastime sort of way. But I would never act on any forum advice-- including mine--- without checking with a knowledgeable pro first. I'm not talking about things like what kind of paint or varnish is good. I'm talking about "why is my engine doing this" kind of stuff.

Fighterpilot said:

... on an earlier trip we had a rear fresh water hose blow off and the engine and the filter from the looks of it got hot.

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Ah, the "rest of the story."


If the engine got hot enough to alter the appearance of the air filter you might want to take a closer look at that engine.

RickB said:

Ah, the "rest of the story."


If the engine got hot enough to alter the appearance of the air filter you might want to take a closer look at that engine.

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amazing how often there is "something else"....makes me smile....can't count how many times after helping someone for hours and THEN you get the rest of the story...

Ah, but the rest of the story is, lost water hose was days ago and the engine ran great while I spent about 1/2 hour at the dock checking out the tach with a laser sensor, and than for 3 hours on the next trip out at 2400rpm with no problems. I think the final "coup" was the all the smoke, and soot that was taken into a marginal filter when the other engine exhaust elbow failed.

Fighterpilot said:

Ah, but the rest of the story is, lost water hose was days ago and the engine ran great while I spent about 1/2 hour at the dock checking out the tach with a laser sensor, and than for 3 hours on the next trip out at 2400rpm with no problems. I think the final "coup" was the all the smoke, and soot that was taken into a marginal filter when the other engine exhaust elbow failed.

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very well could be.....

Just check the other air fliter this morning, which I knew was good 4 eingine hours before the debacle. It was covered with black soot as well. Change that too.

Interesting, the only way you can get them out because they fit under the deck with very little clearance is to remove the butterfly nut on top, lift up the housing off the engine, reach in with long pliers and back out the main stem that screws down into the engine block, being careful not to let it fall down into the intake manifold housing, than slide the whole filter sysem out. I wonder if they make an aftermarket k and n type filter adapteer that would work?

Here's my two cents...I wouldn't run an old Cat 3208na at 2400 rpm for any length of time. Just asking for trouble in the short term and premature failure in the long run.

G---Is your observation based on the fact is is an old engine or the fact it is a Cat 3208, or both? It is NA and I believe that engine was built to run continuously at a lower RPM in industrial use at 2400 rpm or so. I have to make sure the props are not too much for it and I have good water circulation, but we will run it at 2400 rpm going and coming from the fishing areas and I'll find out if it was a mistake later on. Your concern, however, is noted.

As a followup to the riser issue--boat mech., suggested I get a new one. He could boil out the old one but felt it might just open up another can of worms, or a the very least, increase the risk for major engine damage later on. I have ordered a riser and am considering ordering two more for the other engine since they didn't look much better than the one I am replacing.

Thanks for you comments.

Giggitoni said:

Here's my two cents...I wouldn't run an old Cat 3208na at 2400 rpm for any length of time. Just asking for trouble in the short term and premature failure in the long run.

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no way 2400 is a problem....400 below max rpm (at least that's what I think it is based on a quick search) on a na diesel is loafing along anyway...careful maintenance is a much bigger deal.

psneeld said:

no way 2400 is a problem....400 below max rpm (at least that's what I think it is based on a quick search) on a na diesel is loafing along anyway...careful maintenance is a much bigger deal.

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Got to agree with you on that one. I was under the impression that a diesel needs a load and 2400 is about right for a 3208n.a.

Sd

Fighterpilot, I'll concede that 2,400 rpm is well within the range of the 3208na. I see that many are run at that rpm. My boat, when full of water, fuel, and gear, weighs about 45,000 pounds. When I pass 2,000 I'm just digging a bigger hole, so I keep the rpm down to 1,650 to 1,800 for day-long cruising. My two cents is all you paid for..!

G--appreciate your two cents--understand your thinking. This is the 4th boat in 7 years and think we may have figured out what we want. We looked at boats and sea trialed boats from Galveston, Tx, to Indiantown, Fl. over a 9 month period. Main needs were children friendly, sleep 6, flybridge, and cruise at 15knots, loaded. Only considered those power by the Cat 3208 or the Cummins 6 cyl. and the big one--$40,000 budget.

Based on literature the present boat should meet the requirements, and has, thus far. We knew this boat was mechanically a project boat but we got it bought for 1/2 our budget which lets us make the necessary improvements. It sometimes is argued that one should spend more and get a boat that isn't a project boat, but by and large a prestine boat is hard to find. I'm sure this forum has many such boats, but not many for sale and many on the West Coast. Cost to get the boat to the panhandle of Florida was also a factor. Found this boat just 40 miles from out dock.

Anyway, thanks for your comments. Appreciate all the two cents worth since they add up and help me out. FP

Years ago when we were looking for a GB42 and found one with Cat 3208s, I kept my fingers crossed that the hull and engine surveys would be favorable because I really wanted those 3208s. The surveys showed that the POs took good care of her. Since then, my Cats have run flawlessly. I'd sell the boat tomorrow if I could keep the engines! Not really, I like the boat too.

Fighterpilot, You get your boat running to haul her out? You at Pelicans Perch?