w124 1988 190 2L Pierburg Carb Mixture Screw

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deanoandrew

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Hi I hope someone can help me with this.

My 1988 190 is running sweet, but is running too rich, causing the emmissions to show as around 7 ( whatever you call its ) rather than the 3.5 the MOT man requires.

I am wasting petrol , which at current prices is just daft, and obviously killing the polar bears and as they are vicious little buggers i do not want to upset them !

The car has a Pierburg 175cd carb, can someone please explain to me where the mixture screw is as I can not seem to find it !
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pictures or drawing would be really helpful.
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Many thanks in advance
 
I have an old volvo that has a pierburg 175cd. There is a screw slightly recessed in one corner of the carb which you can adjust the idle speed.

However for full adjustment I gather this is done internally within the carb via the needle- never been brave enough to play with it myself and have been lucky to find someone who knows what they are doing to tune it perfectly.

CO emissions always well within MOT limits (<2 I think) when it is in good form and serious improvements to fuel economy – well worth doing.

EDIT: should add my pierburg had a bit of an overhaul a few years back – new diaphragm, needle and lots of cleaning. The results were very noticeable, in a good way.
 
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I have an old volvo that has a pierburg 175cd.


A long time ago friend had an old 244 with Stromberg 175CD that must've been made up from two carbs because the top was an earlier type with no needle adjustment and the bottom was a later type with no jet adjustment.

It ran so rich someone had taken off the cold running compensator from the side of the carb to create and air leak. Fitted a new compensator and it was even worse, so what to do....:dk:

Easy...take the bottom off and tap the jet upwards with a hammer....

sorted...:D
 
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A long time ago friend had an old 244 with Stromberg 175CD that must've been made up from two carbs because the top was an earlier type with no needle adjustment and the bottom was a later type with no jet adjustment.

It ran so rich someone had taken off the cold running compensator from the side of the carb to create and air leak. Fitted a new compensator and it was even worse, so what to do....:dk:

Easy...take the bottom off and tap the jet upwards with a hammer....

sorted...:D


Yes, mine is a 244. Has been ferrying me round since I was a baby so I am quite attached to the old thing.

Carb has been the only real weak spot on it, needing a bit of TLC every year or two. Other than that it would put anything other than old mercs to shame in terms of durability :)
 
if its the same as a W123 175cd carb then the crew is on the underside of the carb.. you first need to undo the 17mm nut then screw.

I would let the MOT garage do it... they will get it spot on with their machine.
 
as above, but it is a 22mm nut. the shut off valve will need to be screwed in to weaken, out to richen, after loosening this locknut. always nip up the nut before checking the mixture because it will make a difference. and also as above, you cannot really do it without a gas analyser.
 
as above, but it is a 22mm nut. the shut off valve will need to be screwed in to weaken, out to richen, after loosening this locknut. always nip up the nut before checking the mixture because it will make a difference. and also as above, you cannot really do it without a gas analyser.
Agreed. Only turn it a fraction at a time though.
 
Thanks for the replies guys :D
 

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