E-Class (W114/W115) 1968-1976: All Models

Help with vac hose question to fuel pressure/RETURN valve thing after converting carb

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Old Apr 8, 2016 | 12:18 PM
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1973 280C M110 Automatic
Help with vac hose question to fuel pressure/RETURN valve thing after converting carb

Hi All.

I’m 80% done, with my Weber conversion on my 1973 280C M110 (automatic)...the Weber (redline kid) is on now in place of the single Solex. But... I'm stuck - puzzled by one (or three things I hope you can help with:

+ the Solex had 4 vac hoses connected to it! Weber has only 2 nipples.

+ that leaves me with 2 free/disconnected hoses. I can cap them off back at the pots they originate from (near the left wheel well) okay, but then i have another unspoken for vacuum nipple:

+ On the fuel line going into the carb there is a kind of 3 way valve thingee... It's the fuel pressure regulator / FUEL RETURN VALVE. and on (mine anyway), there is a vac nipple on the bottom, and this is one of the lines that *was* connected to the SOLEX, BUT NOW HAS NO HOME.

WHAT DO I DO WITH THIS VAC NIPPLE ON MY EXISTING VALVE?

Do I…

a) cap it off on the fuel pressure / return valve and use it as is?

b) connect it to one of the now-free vac hoses that no longer needs to be connected to the carb (since the webber only needs 2 and the Solex needs 4)

c) remove the fuel pressure reg/return and get another model (part number?) that does not require a vac actuator of any kind.(if c, i need a part number. the blue workshop manual shows a part just like it without a vac hose on it, but no number, and mentions that this is the new (in 1975) style replacing the old style (eg. mine) and doesn't need vac)



THANKS!
Tom.
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Old Mar 5, 2018 | 03:45 PM
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