The Mercedes 190sl was equipped with a 1.9L inline 4 fed by 2 Solex PHH 44 carburetors. These things are complicated, expensive and of course troublesome. For one, the front and rear carburetors are different on cylinders 2 and 4, having a vacuum operated venturi of sorts on the second barrel of each unit for smoother running and better response. They worked fairly well but there were a lot of steel parts wearing against aluminum. Things would start getting loose as the independent throttle shafts wore, venturi's worked loose and they grew further and further out of tune as people tried in vain to adjust them or rebuild them with abslolutely no success.
The other major problem was the inability to withstand a lot of heat, warping the body causing the venturi problems and misalignment of the throttle shafts for starters. The exhaust manifold is directly below them. What did they think was going to happen? Many a 190 has received long term garage duty over these. They are truly a nightmare. There are 2 versions; one is cast (Germany) and the other Mikuni version mad of light alloy. Both had problems and there's one guy in Germany that has the equipment and know how to fix them an it will on cost you around $6,000 bucks. If you're a purist, go for it. You can get them used, but they are either going to be Mikuni or junk, most often junk
In steps Weber (Redline) with a bolt on kit with universal linkage and adaptor plates for the plenum. The Weber’s bolt right on and look good. It soon becomes apparent that neither the original or universal throttle linkage will simply bolt on. Don’t bother calling, they won't know. The second problem was the adaptor plates. They give you those tin redline air filter assemblies, but you can't do that! It's a Mercedes!
It's really not that big of a deal. The plates require a milling machine and some welding skills. Farm it out, otherwise follow this picture tutorial to see how to fix it and make it look original.
This is what your original carburetor setup should look like:
1) Throttle control cable 2) Plenum 3) Rear carburetor and metal fuel line 4) Front carburetor and metal fuel line 5) Pivot Assembly 6) Machine crimped fuel line and T 7) Pimary linkage rod.
Separate everything from the carburetors, you're going to need some of it. The plenum isn't going to fall off. See the 6mm studs and nuts from the top with a wave washer, flat washer and a nut? Same on the bottom, and no your arm won't fit in from the side, back or top. Reach through the front. There's a bracket from the base of the plenum to the engine block. This one can be reached fr;om the side. It should be a 9mm x 1.5 (15mm wrench) The on the block is a 10mm x 1,25 (17mm Wrench) Just loosen it until the bracket swivels out of the way.
1) Choke Cable 2) Pivot Arm 3) Carburetor Throttle Linkage 4) Throttle Return Spring 5) Primary Throttle Linkage Rod
1) Primary , Linkage Rod 2) Metal Fuel Line to Pump
1) Manual Priming Fuel Pump 2) Reserve Fuel Switching Valve
Get familiar with your Webers.
1) Idle Air Bypass 2) Idle Air Corrector & Jet 3) Air Bleed Screw 4) Choke Securing Screw 5) 3/16/5mm x 1,0 Throttlle Rod. LH thread at one end. Required bends are marked.
1) Fuel Inlet Banjo 2) Throttle Rod 3) Primary Throttle Rod 4) Plenum Adaptor Plate
1) Fuel Inlet Banjo 2) Linkage Bracket Bolt to Base 3) Throttle Shaft 4) Required Bends
1) Rear Carburetor Throttle Linkage Rod 2) Pivot Arfm Assembly 3) Front Carburetor Linkage Rod 4). Primary Throttle Linkage Rod
1) Plenum to Carburetor Adaptor PLate
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