I am a pretty good mechanic, and have worked on a great many of mercedes cars, and do a lot of marine diesel work as well.
I have a customer who asked me to look at his freshly installed twin mercedes 2.4L diesel marine engine installation. Everything was reportedly rebuild.
One motor runs great, easy start, no smoke, and good power.
The other engine, port side, runs exceptionally bad.
Random missing, horrible idle, very bad smoke, below 2500RPM or so. The engine does make power however and does not smoke when run hard.
I checked cam timing, compression, valve clearance, fuel quality, and primary pump pressure. had all the injectors checked. all is good.
No blowby. checked pump timing, but cannot do drip test, due to a non automotive pump. I cannot remove the spring and ball assembly.
I did check pump installation, and found the marks on the pump to line up at 24BTC. The missing at idle is really bad and random, its not a miss that is related to one cylinder, it much looks like a gas engine that has excessively advanced ignition. I did try to retard injection timing, no difference, still runs bad, advancing has the same result.
I pulled the pump again, and will send it out for inspection, but as a curiosity, is it possible the advance mechanism in the engine might be broken? causing random, and rapid timing changes?
who might have some insight here?
The engine is mechanically competely identical to a 240D engine.

Henri.

The timing device could be the culprit, however I do not believe I have ever heard of one giving problems. I've only been at this a year or so though so my knowledge is not all encompassing. If the injection pump checks out the timing device would be the next logical step. It is located under the vacuum pump (is there a vacuum pump on a marine 616?) and it is a fairly involved procedure to remove it.

Did you double check that there are no restrictions in the intake?

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Just a longshot.... but fouled pre-combustion chambers and/or blocked with glow plug loop fragments?

Just want to relate a problem my Father had one time. He had a 32 ft Owens with 2 327 Chevy gas engins. He had his mechanic tune them up. One run great, the other wouldn't even start. The problem was that the engins turned in oposite directions. I believe it was the left engine that ran CCW and the right engin ran CW. Is it possible that is the problem? Could one have been rebuilt with the wrong parts, for instance the advance may be retarding instead of advancing? Could the timing be set to 24 deg ATDC? Just a possibility.

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84 500 SEL (307,xxx miles)

now that last post is really thought provoking.

i have no idea on that but can understand why it would work.

do the engines draw fuel from the same tank?

sounds like it could be fuel to me.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Sounds very much like timing to me. In most newer marine applications the gears are 100% strength in forward and reverse- so it's the gears which change the rotation of the propshaft. The starboard prop turns clockwise from the stern view; the port CCW. Obviously from the helm the controls are set properly. Your best bet is find the compentent local MB independent mechanic and ask him to check the engine out after finding out as much as you can here. Why is the IP different than the Bosch found on automotive applications so that you can't do a drip test? BTW your engine is called a OM616. What is the HP- 67? That's standard for the engine.

Thanks for all the info, indeed I have a OM616 with 67HP. Indeed some marine engines do excist counterrotating, but mainly engines where the timing gear allows this, like a standard good old American V8, and some V6's . In this mercedes engine reverse turning would destroy timing components, so both engines do turn the same direction. Sometimes The gearbox allows for a revese turning prop by changing forward and reverse controls, but anyhow this is outside the scope of this forum. The fuel issue I did adress by using the fuel source from the good running engine , there was no difference.
I do have to say however that the fuel that the bad running engine uses was very very red, compared to the other engine that was more normal colored.
Now in the US we add a red die to fuel used for off road application, but this boat was converted to diesel and only went to the diesel pump once. The fuel that went into the both tanks was the same. So I am curious about the very red appearance of the fuel for the bad running engine, it had a varnishy smell too, which makes me believe that maybe it is trying to dissolving old gas that might be left in the tanks. Anyhow I did change fuel source, and there was no difference.
However maybe the mix of gas and diesel migh create havoc and dissolve seals in the pump?
Anyhow, I will send the pump out for inspection.

Henri.

Was there gas remaining in the tank and diesel was added to it? If so, could this have damaged the engine or pump?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Hebri-
always a good idea to have your location and type of car you have so others can have an idea of what is wrong... in your case you'd put location and OM616 marine. If you need a IP I can get a used one for less than just about anyone.

From what he has described it sounds like a marine IP is different from the automotive one.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

I can't believe there is a "marine" IP. I've had four 617's, and 6 MB's and drive a 65 foot sportfish with 3000HP for a living.

Euro and US Mercedes have diffrent Injection pumps...why not marine engines?

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Miss does sound like low I/P internal pressure...aerated fuel ?....being as the miss is random. Check the outlet valve on the pump ?
Swap it for the other engine.

If you have time..swap I/P's.



.

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"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

Mercedes does not make a "marine" 616... (MTU "makes" all the MB marine engines, and none of them are under 700HP) other companies may convert this MB engine for use in a boat... but they would not change the IP. And if they did... why could you not use the drip method... which is why we are addressing the question...? Until there is more info or we have a more experienced opinion it's gonna be tough to help. I think the IP is not timed right... like it's skipped a tooth. Good logic however on the thought train...

to settle the IP issue.. if you could take a pic of this IP on your "marine" 616 it would help much my friend.. thanks