Stromberg 175 CD on '76 230.4 - H.E.L.P.

[MunichTaxi]

First, remove the float bowel, and see if there is a rubber O-ring on the main jet stem.

If this O-ring exists in your carb, make sure it is in very good conditon. It may look good, but if you try to take it off, it comes off in pieces.

The main carb jet is only metered properly when the rubber O-ring on the main jet seals in the bottom of the base of the float bowl.

[tr1cky]

Can anyone verify that the Pierburg and Stromberg are the exact same unit?
Are parts including rebuild kits directly compatible?

Originally Posted by arkie

Last Wednesday I picked up a pretty nice 1976 230.4 with a Pierburg (Stromberg) 175 CD carburetor. It has been driving me NUTS - when I got it all of the vacuum ports on the carburetor didn't have hoses on them, the water mass for the choke system was missing, and the thing idled way too fast. I found some nice information on the carburetor - it seems that Pierburg took the 175 CD design over in the early 80's - don't know how it made it onto my car, though. I found a 75 230 in the junkyard and pulled the complete carburetor off - and started stripping parts off of it and getting everything hooked up as it should be and got the idle set down to proper levels. Everything seemed to be improving until tonight. The car has been running way too rich, so I started dissecting the parts carb to see how the "choke" mechanism worked. I took it apart and found everything gummed up, so I cleaned it including cleaning the enrichment jet so that is doesn't stick anymore. I found the same problem on the carb on the car (enrichment jet stuck in the depressed warmup mode) , so I just took that entire choke housing and installed it on my carb. The car was running pretty good for a while (maybe 15 minutes)as it was idling, then it started misfiring a little. The car was running very smooth before now, and it just isn't idling as good as it was. I have cleaned the rotor and put a new distributor cap on it in the last few days - I am waiting on plug wires to come in. I cleaned the points with a piece of paper (and they were clean), but I don't have any information on the gap in the points to check it. Maybe the ignition needs going through, or maybe I have the mixture messed up now that the carb is getting straightened out. Any suggestions or thoughts appreciated.

[gs sparhawk]

Apologies for highjacking but----I have been looking all over for a jet that goes in the bottom of my 175 fuel bowl. Nothing anywhere in the world--so the parts guys say. Need something to keep the nail from losing the shoe, that makes the horse go lame. anybody have a suggestion short of a different carb?

Otherwise, The tuning of the stromberg 175 is a bit different than some. It is a matter of balancing the jet adjustment to the throttle response. It is explained in a post by the University Motors site in Michigan. John Twist has a number of articles he did for Strombergs and his tips made it easier for me, anyway.


Sparky

[JeffreyNMemphis]

Sparky,

I have some Zenith carbs sitting on the shelf. Are the parts interchangeable as tricky asked?

Can someone tell us what is the difference between a stromberg, Zenith Stromberg and Pierburg (Stromberg)?

[tr1cky]

Originally Posted by JeffreyNMemphis

Sparky,

I have some Zenith carbs sitting on the shelf. Are the parts interchangeable as tricky asked?

Can someone tell us what is the difference between a stromberg, Zenith Stromberg and Pierburg (Stromberg)?

From my research, and it doesn't go beyond the first few pages of Google it appears that Pierburg licenced or purchased this design from Stromberg for the 175. I could be wrong, but that's what I gather. The Pierburg being used as an OEM in many SAAB and Volvo models in the 70's/80's and the Pierburg 175 as I've found may have even been used through the late 80's and perhaps beyond on non US Mercedes.

What i haven't been able to find is whether or not the parts on these carburetors are completely interchangeable. If I had a Stromberg 175CD I would start moving parts from one to another to verify, but aside from that I've received nothing definitive.

[gs sparhawk]

Jeffrey,

Soime parts my indees exchange. Mine uses a screw-in, adjustable (in & out) jet that screws up into the bottom of the fuel bowl and the long needle from the diaphragm drops down into it to change the mixture according to the load demand. That jet is accessible from the outside and has an "o" ring set into a recess at the bottom end that seals the bowl from leaking gas. I need that jet since mine fell out on I-29 here in town. a two-bit piece holding up the whole car. If you have a likely part, I'd be appreciative. It is what made me nuts for several months and determined to do a throttle body install.

(& I do remember some of the adjusting sequense on that carb, too)

Sparky

[gs sparhawk]

I'll have to consider finding a whole --complete carb, I guess. The part I need is troublesome. I can probably fit any 175 that was made as a single for a four cyl. Would rather have the car run than be picky about the "correct "parts. Sell one?

Sparky

[mercmad6.3]

Thousands of BMC, Hillman,Triumph and Nissans came with the Stromberg CD carb. There are plenty of places out there dealing in them . Try google for MOSS UK or Rimmer Brothers UK .

[AnnyR]

I've read the comments, etc. I know it is over 10 years old... but I think I might have the same problem. Have my W115 for 3 years now, and it "breaks" every now and then. Now it won't start. Not the battery. It also "shakes" when switching off like it's restarting itself. That has been an issue from the start, and I've been struggling to get it right. Every time the mechanics do something else that "works" but after a while we are back to square one. All parts in the car has been replaced, re-done, attended to. But still the same. It will only be perfect for 2 weeks to almost 2 months. I'm so fedup and don't know what to do. It heats up as well, but there is water, and the fan works. there are just so many problems, that I don't know anymore.

[JeffreyNMemphis]

Driving a classic car can be frustrating and also rewarding with a pleasure of accomplishment when solving the puzzle.

Check the bottom of the carburetor with a metal straight edge ruler to confirm that the carburetor is not warped. Sometimes a mechanic can tighten down the carburetor on one side or another that creates a vacuum leak and warps carburetor.

If your carburetor is warped it can be made "true" again.

Sometimes the heat gauge stops working correctly. Use a laser thermometer ($25 from Harbor Freight) to confirm temperature.

[mercmad6.3]

Now it won't start. Not the battery. It also "shakes" when switching off like it's restarting itself.

What you describe is bad ignition timing, which causes the engine to run hot, and when you turn it off the engine is very hot inside, either glowing hot spark plugs (which will break down making it hard to start) or carbon deposits . Now,in this sort of situation I would check that the ignition opoints are new, they are in good condition and set to the correct gap. Next ,get the compression checked ,the valve clearances set correctly and the timing chain checked for wear. If it all checks out ok, the spark plugs must be replaced with the correxct type for your model engine and gapped correctly . I would also check that the water pump is circulating the coolant correctly and the thermostat is opening.

[optimusprime]

Have you checked the fuel to air ratio?

[optimusprime]

Problems i have founed with the Stromburg 175 CD is the float in the bottom of the carb .The do get holes in them .Then as it fills up the chamber they dont cut off the fuel .And you will need the large allen key type tool to adjust the mixture . Over in the uk we have a clever little toll that you pop inthe engine ,in place of the spark plug .In the base of the tool you have a glass bottom .Idea is,, that when fitted in the engine , and running that you can see the combustion in the cylinder and you know mixture is set right when it shows blue. I came across my old adjusting tool in the garage yesterday.No use to me anymore . A lot of these Strombergs were fitted in pairs on the Triumph 2000 .But more of a problem than the old SU carbs of the day..A lot of owners swaped out the Stromburgs for the SU much better to tune up in pairs or tripple .Lots of info on the Stromburg if you go to Google serch engine ,,look to the top right you will see images. Then click on it , then in the search box you put Stromburg 175 CD ..

[JeffreyNMemphis]

Originally Posted by mercmad6.3

What you describe is bad ignition timing, which causes the engine to run hot, and when you turn it off the engine is very hot inside, either glowing hot spark plugs (which will break down making it hard to start) or carbon deposits . Now,in this sort of situation I would check that the ignition opoints are new, they are in good condition and set to the correct gap. Next ,get the compression checked ,the valve clearances set correctly and the timing chain checked for wear. If it all checks out ok, the spark plugs must be replaced with the correxct type for your model engine and gapped correctly . I would also check that the water pump is circulating the coolant correctly and the thermostat is opening.

That is a very intelligent answer! I am glad to see that you are still here and contributing!!

[optimusprime]

Colour Tune is the little tool that you pop in the engine instead of the spark plug .In the top it has a glass window .When the carb mixture is right, it will glow blue.