Carb Nozzle fuel leak

1961-1968: a.k.a "Finnie" or "Heckflosse" models
190, 190D, 200, 200D, 220b, 220Sb, 220SEb, 230, 230S, 250SE coupe, 280SE coupe, 280SE 3.5 coupe, 220SEb cabrio., 250SE conv., 280SE cabrio., 280SE 3.5 Cabrio., 300SE, 300SE coupe, 300SE conv., 300SEL
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dynamike
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Model you own: w111
Location: Brisbane, QLD

Carb Nozzle fuel leak

Post by dynamike » Sat 09 Sep, 2017 10:14 am

Took the car out after changing the engine mounts and noticed a smell of smoke. Thought it was just grease burning off the exhaust but noticed a fuel leak near the carburettors as per photo below.
20170909_081122.jpg
Any thoughts on why it would be leaking there? From the diagram it looks like there's a diaphragm - could that be it? Also, I assume once I drain the fuel line to work on it there wouldn't be any pressure pumping more fuel through?
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1965 220 Sb Sedan
1962 220Seb Sedan (stripped for parts)
http://ozbenz.net/viewtopic.php?f=9&t=23626

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Tony From West Oz
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Re: Carb Nozzle fuel leak

Post by Tony From West Oz » Sun 10 Sep, 2017 12:23 am

While I do not know what the item below the banjo fitting is, I do know that Banjo fuel fittings sometimes do leak.
Before doing anything else, try just tightening the bolt a little (no more than 1/12th of a turn) and see if the leak is fixed.
If it does not fix the leak, then replace the copper (aluminum) washers on each side of the banjo fitting (where the fuel hose connects to).

They are cheap and easy to replace.

If the fitting still leaks, you may need to check the device in the bolt head.
Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

'83 W123 300D 325000km (Wife's car Josephine - sold).
'84 W123 300D replaced good OM617 912 with OM617 952 and enjoyed having good acceleration for the first time since first driving a 300D in 2002 - became engine and trans donor for 300CD Turbodiesel conversion. Now parted out.
'86 W124 300D sold (Wife's old car - sold )
'85 W123 300CD, 275 000km (Fatmobile) rebuilt turbodiesel from previous Fatmobile transplanted into 280CE (occasional tourer)
'99 W202 C250 Turbodiesel (my darling Wife's car - Sold)
'98 W202 C250 Turbodiesel (my car - Sold)
'06 Ssanyong Musso Crew Cab 2WD Ute (OM662 diesel and Auto Transmission)

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dynamike
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Model you own: w111
Location: Brisbane, QLD

Re: Carb Nozzle fuel leak

Post by dynamike » Sun 10 Sep, 2017 7:20 pm

Thanks for the reply. Took it out to have a closer look today and everything looked fine. Tightened it all back up and no more leak.
20170910_153703.jpg
Still curious as to what the actual function of it is? Increase fuel pressure when accelerating hard?
20170910_152352.jpg
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1965 220 Sb Sedan
1962 220Seb Sedan (stripped for parts)
http://ozbenz.net/viewtopic.php?f=9&t=23626

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Tony From West Oz
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Re: Carb Nozzle fuel leak

Post by Tony From West Oz » Sun 10 Sep, 2017 10:31 pm

This looks like a valve that is actuated by the float in the carby float chamber. When the level is low, the float falls, pushing down on the pin, opening the rubber valve, which allows fuel into the float chamber, the float rises and the valve closes again.
Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

'83 W123 300D 325000km (Wife's car Josephine - sold).
'84 W123 300D replaced good OM617 912 with OM617 952 and enjoyed having good acceleration for the first time since first driving a 300D in 2002 - became engine and trans donor for 300CD Turbodiesel conversion. Now parted out.
'86 W124 300D sold (Wife's old car - sold )
'85 W123 300CD, 275 000km (Fatmobile) rebuilt turbodiesel from previous Fatmobile transplanted into 280CE (occasional tourer)
'99 W202 C250 Turbodiesel (my darling Wife's car - Sold)
'98 W202 C250 Turbodiesel (my car - Sold)
'06 Ssanyong Musso Crew Cab 2WD Ute (OM662 diesel and Auto Transmission)

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Mercmad
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Re: Carb Nozzle fuel leak

Post by Mercmad » Mon 11 Sep, 2017 12:55 pm

Fuel return valve, when idling it opens and excess fuel returns to the tank. Open the throttle and it closes giving more fuel to the carbs. it's basically there to prevent vapour locks

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Tony From West Oz
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Joined: Mon 20 Jun, 2005 10:04 pm
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Re: Carb Nozzle fuel leak

Post by Tony From West Oz » Mon 11 Sep, 2017 7:20 pm

You learn something every day.
Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

'83 W123 300D 325000km (Wife's car Josephine - sold).
'84 W123 300D replaced good OM617 912 with OM617 952 and enjoyed having good acceleration for the first time since first driving a 300D in 2002 - became engine and trans donor for 300CD Turbodiesel conversion. Now parted out.
'86 W124 300D sold (Wife's old car - sold )
'85 W123 300CD, 275 000km (Fatmobile) rebuilt turbodiesel from previous Fatmobile transplanted into 280CE (occasional tourer)
'99 W202 C250 Turbodiesel (my darling Wife's car - Sold)
'98 W202 C250 Turbodiesel (my car - Sold)
'06 Ssanyong Musso Crew Cab 2WD Ute (OM662 diesel and Auto Transmission)

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Bartman4800
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Location: Perth WA

Re: Carb Nozzle fuel leak

Post by Bartman4800 » Sat 16 Sep, 2017 7:40 pm

To add a bit of info: the diaphragm will perish over time but is now available through mbclassics.de or ruddies Berlin.
1963 220 Sb Sedan "Kermit" (Australian Assembly)
1960 220 Sb Sedan "Zum Schlachten" (Early German Assembly, with a torsion bar spring for the bonnet) - Stored in Country WA
1981 Subaru Brumby 1.8 with Weber and 5-speed box "little utie" - Sold to another enthusiast!
2006 Ford Focus "missus car"
2002 VW Passat V6 30V Station Wagon (my new commuter bus)

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