car will not stay running - Mercedes-Benz Forum

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post #1 of 33 (permalink) Old 07-05-2004, 07:16 PM Thread Starter
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car will not stay running

Hi everybody,
My 1971 Mercedes Benz 250 sedan recently developed a problem which I cannot figure out.
When I start it up I have to keep the accelerator floored to keep it running. I thought at first I might have gotten some bad gas so I put in two cans of dry gas thinking that would fix the problem, much to my disappointment it did not. So now I believe the problem lies somewhere in the dual carbs. Anybody have an idea what it could be?
Thanks
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post #2 of 33 (permalink) Old 07-06-2004, 09:38 AM
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RE: car will not stay running

You have fire and fuel. Could it be a bad fuel pump? There is an electric pump at the back, and if it is original, it very well could be failing. A higher acceleration might suck up enough to run it, but then fail at slow idle.
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post #3 of 33 (permalink) Old 07-06-2004, 10:39 AM
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RE: car will not stay running

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post #4 of 33 (permalink) Old 07-06-2004, 06:25 PM Thread Starter
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RE: car will not stay running

I think it very well it could be a bad fuel pump because when driving at high speed it goes along okay. When I slow down for a stop the engine cuts out,and I have to restart it shift into neutral rev the engine then put it in gear. Also I have noticed more fuel consumption lately. It also is the original fuel pump so it could be going. Are there two fuel pumps, one in the tank and one in the line? And if so which one is likely the culprit?
Thanks
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post #5 of 33 (permalink) Old 07-07-2004, 02:13 AM
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RE: car will not stay running

more like a split Diaphram in the carb and out of ballance between carbs, its not listed as haveing electric pump
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post #6 of 33 (permalink) Old 07-07-2004, 08:42 AM
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RE: car will not stay running

teky is correct. A 1971 250 does NOT have a electric fuel pump.

Did someone add a in-line fuel filter somewhere that is clogged ??

jay
IL

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1971 W113 280SL
_______________
..the road to nowhere. . .leads to me.
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post #7 of 33 (permalink) Old 07-07-2004, 07:20 PM Thread Starter
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RE: car will not stay running

Yes there is an inline filter, but I've already checked that and it's in good shape. If there is a mechanical pump where would it be located on the car?(1971 250 Sedan)
Thank you for helping me out I really appreciate it
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post #8 of 33 (permalink) Old 07-08-2004, 02:04 AM
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RE: car will not stay running

if you found the inline filter just trace the pipe back to the engine, normally on the cyclider head driven by the camshaft
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post #9 of 33 (permalink) Old 07-12-2004, 05:07 AM
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RE: car will not stay running

The fuel pump is placed on the engine block, close/behind the PS pump. But most likely is your carbs out of adjustment. Tune them by the book or not at all.
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post #10 of 33 (permalink) Old 07-13-2004, 07:00 PM Thread Starter
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RE: car will not stay running

I had some time the other day and I looked at the mechanical fuel pump. I knocked on it a couple of times with a screwdriver just to see if it would do anything, I got in and started the car it idled for about two minutes without me having to keep my foot on the accelerator pedal. Could this mean that it is fuel pump? Iam very hesitant about doing more work to the carbs as I've had them looked at a couple of times and fixed but it is very possible that they could be the problem. Teky said it might be the diaphragm. Where abouts is the diaphragm in the carbs? Are there two,one in each or is it in between the carbs?
Thanks
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