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671 TIB - Heavy Black Smoke

Capt T

New member
My 1989 Viking w/ 671 TIB's blows heavy black smoke when trying to turn more than 1000 RPM's. I have cleaned the intercoolers and air sep filters as recommended by a J&T mechanic. Any suggestions?
 
Black smoke=partially burned fuel which could be one or more of the following:
1. Too much fuel being delivered.
2. Not enough air being delivered for complete combustion.
2. A combination of both of the above. Unusual but it happens.
4. Severe overloading. This would typically only occur at full throttle.

That's what I know. Everything else is guessing. Your post intimates it is happening to both engines so that might be a clue.

The first thing I would want to know is all about the turbos. Are the turbos "coked" up or dirty enough that they are not spinning up properly? Are any of the blades binding or damaged? Has the engine received proper oil service and are the turbos getting an adequate, clean supply of oil so that the bearings are, and have been, properly lubricated?

See? I told you I am guessing.... and I'm guessing air delivery.

Other items to check off for good engine breathing would be:

Can the engine room vent for good air flow? Is all air ducting clear un-kinked and properly connected?

Is the exhaust system properly connected and routed so that the turbos can be powered efficiently?

When was the last exhaust valve adjustment? These engines don't like tight valves as they need "scavenged" fresh air to breath well. Additionally tight valves will also limit turbo boost.

Hope this is of some help.
 
jgmo - thanks for your input. The air problem seems to be ok but I'll recheck. Turbos spin free & not damaged. I ran the boat with the engine hatches open & the problem was the same. Don't know when the exhaust valve was last adjusted so I'll check that & also the fuel system. Could a fouled bottom & props cause the overlaoding enough to be the problem? Your "guesses" are appreciated?
 
It's both engines doing this? If so, then I suppose a dive on the props would be in order to check for anchor line wrapping or something. Does the hull have a huge beard?

Sorry to beat your dead horse but I am still guessing air flow. You never mentioned (and I never asked) about the air filters. Check the air inlet strainer screens on the blowers to see if they are nice and clean.

If you find some clogging there, then it is possible the liner ports are starting to carbon up and close. If this problem slowly came on over a period of time these are possible causes but not too likely if you noticed it all at once. My problem is that I'm guessing blind with no knowledge of how many hours your engines have or their general condition and maintenance.

Going back to the exhaust, these engines do not like any restriction in the intake OR in the exhaust system. The maximum exhaust restriction allowed is only 4" of water at full rpm. That isn't very much. Not much more than a 2 liter, four cylinder gasoline car allows.

You may be getting to the place none of us ever wants to go because of the expense. Visual inspection can only get you so far and ultimately, some science, specific product knowledge and special tools need to be applied to "figger" it out.

I'll be happy to "chew" on it with you as long as you like though so don't hesitate to ask. I never was the best but I done ok fixin' these things over the years.
 
The engines have 780 & 800 hrs on the gauges ( I'm guessing smoh). Due to health problems I haven't been able to use the boat much and it sat idle most of the last 2 years when the problem started. Here's what happens. The engines start fine and run perfect at low rpm's (under 1000). When I throttle up to try to get on plane the starboard engine starts to smoke heavy black and then after maybe 30 seconds the port engine does the same. I am never able to get past 1200 rpm's. I cleaned the air filters and intercoolers after they were inspected by a former J&T mechanic (now in business for himself). He felt certain that would solve the problem. I'm sure this was necessary but the problem remains the same. The next step will be to check out your suggestions. I'm doing that tomorrow with a friend who has some diesel engine experience and will let you know what we find. Thanks again for your help - it is really appreciated.
 
Capt T,
I know about them health problems me own self. Just had spinal fusion done. What fun!
Sorry you're having problems and I'm very glad to try and help.
After your further explanation, I have a few more questions.

After sitting for so long, I trust that you have serviced the fuel filters and water separators? Hopefully before initial start up? The fact that it starts easily and will "fast idle" is encouraging but after that long a lay up, fuel quality always concerns me. Especially the formation of algae.

Let me put it this way; I would never use fuel that has been sitting for two years in a vessel's fuel tanks. I would drain and refill. But, most boat owners haven't seen what I've seen growing in fuel tanks.

What I would like to know now is, will both engines (independantly) throttle up and reach "no load" (2150 rpm or so) when out of gear?
 
To be clear the boat was not completely layed up. I did use it a few times each season. I added fresh fuel each year to the tank since that time to equal 200 gals +- per season. I also added fuel additives during fill ups and at lay up. I'm embarrassed to say that after checking my sevice records the fuel filters / water separators were last change in April 2008.
I'll recheck but I'm fairly sure that each engine will turn 2150 - 2650 rpm with no load in neutal. I'll confirm. On Thursday I'm having her hauled to clean the bottom and props. I also ordered filters from J&T for me to replace. More to follow.....
 
Same problem,88 Ocean 44, both turbos froze up over winter, corrosion on turbine side, caused by bad cast iron elbows. Removed elbows, water jackets non existant. Just received rebuilt turbos from Johnson & Towers. New stainless elbows being made at Marine exhaust in riviera beach Florida. Cast iron ells from J&T will not be available for three months. Stainless ells cost $2568. Turbos are around $2500.
J&T told me that bad elbows allow some salt water to hit the turbine bladesand casing raising hell with them. I loosened mine up with penetrating oil but decided to replace them since they are original, 23 yrs old, 2000hrs. iron elbows are $558 if you can find them.
 
Well, that's good news about having run all that fuel through. Yeah, you need to be more diligent about those fuel filters. Just a small amount of water getting through can damage your injector tips. Make sure that you give those cutlass bearings the eagle eye when she's out of the water. I'll be interested to see what your findings are.
 
Don T - My boat has been used on the Chesapeake so I don't experience the salt problems that you do. I'm hoping that I don't have to go down the road you are on for the obvious reasons....$$$$ I'll continue to work on what I can and see what happens. Good luck with your Ocean.
 
Yes try no load nuetrel for 30 seconds and watch for smoke one engine at a time. Still smokes, straving for air most likely check air supply to turbos and pressure readings after. Black smoke is to much fuel not enough air.
 
Dont forget Injectors clogged. When they Spray the fuel will burn, when the Slobber most of the Fuel dont burn.
Why would it ba all the Injectors on both engines?
Fuel or Air.
 
Here's where I am to date. She's been hauled, cleaned and painted. I picked up 200 rpm's doing that. Oil and filters have been changed. Fuel filters were changed and the fuel looks good with no water. I am able to run each engine at no load with no smoke. Under load anything over 1500 rpm's my starboard engine smokes heavy black and will bog down. I have a mechanic coming to check and set the injectors within the next week. Hopefully that will solve the problem. If not I'm probably back to it being the turbo. Any comments or suggestions?
 
You didn't say what the no load speed of both engines turned out to be. Should be somewhere above 2100 and the same for both. If that's the case, yes the suggestion thudpucker gave is a good one if they have a waste gate system. Otherwise, we're back to either too much fuel or not enough air OR, a combination of both which is fairly rare. It's usually one or the other.

Have your mechanic look at the valve clearances while he's there as well as make real sure she is breathing properly with no intake or exhaust restrictions.
 
Sorry, I should have stated the no load rpm's were 2250 for both engines. I have gone to 2500 without a problem but didn't hold it at that speed for too long. I do appreciate your suggestions and will have the mechanic follow up. Thanks
 
Ok, sounds like the governor is set up and working properly. Hope your mechanic has an "AHA!" moment and gets her straitened out for you. Let us know what you find.
 
Installed rebuilt turbos, stainless ells, and new exhaust hoses, [the hoses were delaminating on the inside.] Boat runs well. 2550 on both max. Marine Exhaust of Riviera Beach Florida did an excellent job on the ells. I might add that I cleaned both intercoolers 2 years ago.
 
Glad to hear you got 'em straightened out. Now, don't forget that those turbos live at around 100,000 rpm at full boost so it is critical that the bearings always receive an adequate supply of clean, fresh oil. Don't let those fuel filters go so long from now on either.
Thanks for the feedback and happy boating.
 
Something's mixed up on this thread. I'm happy Don T has resolved his issue. My issue is still open and pushed back due to the hurricane. I'll keep everyone posted.
Capt T
 
What a project this has turned out to be... While investigating my smoking and lack of rpms it became obvious that the water flow from my starboard exhaust was only about 1/3 of the port engine. Everything on the sea water side of the cooling sysrem was checked and serviced. The last thing to remove & inspect was the exhaust elbow. As you might expect it was froze to the turbo and would not budge. In order to get to it we cut a section of the cabin floor out and removed the entire assembly. I took it home and finally was able to separate the elbow. The water jacket was corroded and clogged. I don't know if it can be cleaned. I checked with J&T and new cast iron ells are on back order with no delivery date known. I believe Don T said this earlier. Can't afford stainless - any suggestions?
 
Take a Ball peen hammer and tap the elbow using the back of the hammer. If the elbow does not crumble you can try to clean it. If it is clogged with rust you can tap it all over and work it free. If it is clogged with minerals from sea water you can use some "on-off" or soak it in white vinegar for a day or so.

If the elbows are on back order this is worth a try, But I recommend replacing it as soon as they are available.
 
Yeah, if they're on back order, you should get in line now. Like Chris said, you should probably replace them as soon as you can. You won't be able to get them completely cleaned and smooth inside so it can effect flow. But, perhaps more importantly, they will clog up again in much less time than before.

Try an air chisel on the corrosion you can get to to see if you can break it up some. If you need more reach. you could weld an extension on to a chisel bit. Any old piece of flat, mild steel will do. It will break up the corrosion but bounce off of the cast. (I hope!)
 
10/7/2010 I may know a source for cast iron ells. I can't get ahold of him until after Columbus day. I'll get back to you next week.
Don T
401-301-9279
 
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