Car was running fine until i went over a large dip in the road doing 80mph. Then car began to sputter on acceleration from a stand still. I parked the car that night and when i went to start the next morning...couldnt get it started. I felt as if it wasnt getting spark so i had my mechanic change the cap and rotar. This seemed to fix the problem until i got it on the freeway and i had a hard time maintaining 70mph and the problem steadily got worse. When cruising and excellerating it will go in and out of sputtering and backfires on occation. Is this a carb leak? Something in the ignition? Or....? Please Help! Thank you.

 

i think i would go for plug leads as i had this problem with a 1980 200

 

Sounds like a carburation problem to me, air fuel mixture messed up.

Possible debris in the needle valve or the power valve.

Ouch

 

are the needle valve or power valve hard to replace? When i have the carbs unconvered and pull on the accelerator chain i can hear the back carbmakea "psss" spray sound but onthe front carbi hear nothing...making me think a jet or something in the front carb is blocked.Could this be my problem?

 

OK, first let me say that while I do have some automotive mechanical training and understand the different fuel circuits in a carburator I don't make my living at it, I am a parts expert.

You have two two barrel carburators on your engine and I believe they are staged. That is the rear carb is the primary and the front carb doesn't start to open until you reach a prescribed throttle position on the rear carb. Then the front starts to open and supplies additional air/fuel mixture to the engine.

There is a needle valve in both carburators that supplies fuel to the float bowls from which the engine sucks fuel through the carburators venturi and into the intake manifold. If the needle valve becomes restricted or blocked the float bowl cant keep up with the engines' need for fuel and the engine will start to starve for fuel.

There is only one power valve in the front carburator which supplies additional fuel to its' float bowl at around 55 mph and up when the needle valve can no longer keep up with the engines ever increasing need for fuel.

You might want to look at the linkage between the rear (primary) carb and the front (secondary) carb to see if your high speed bump bent or popped something loose between them.

Try with the engine OFF and the airfilter out of the way push the throttle on the rear carb full open, by the throttle linkage, which should drive the front carb to open also assuming this is a mechanical and not a vacumn operated secondary and I'm not sure of that not having the vehicle where I can get my hands and eyes on it.

In any case the difficulty of disassembly and overhaul of these carbs for someone who knows how to do it is nothing compared to the difficulty of actually finding the parts to do it with, I would guess.

If you aren't comfortable with it don't try it find a good old MB tech and pay him to verify your problem and effect the repair for you.

Mercedes has a classic car center and some parts are still available but you will have to call them with your complete vin and perhaps engine number to check price and availability.
call 1-866-622-5277
to talk to their specifiers
Mercedes-Benz Classic Center
9 Whatney, Irvine, California 92618
Tel: (949) 598-4850
Toll Free: 1-866-MB-CLASSIC
Hours
Mon - Fri 8:00 a.m. - 4:00 p.m. PST
Their Mailform:
http://www.mbusa.com/mercedes/#/only...opClassicForm/