What is this? Fuel cutoff valve?

[xvcs13]

I'm working on a fuel feed issue on my '71 Ghia which has been sitting for 18 months. Blowing out the fuel line cleared things and I've replaced the hoses and fuel filter while everything was pulled apart.

However, there is a diaphragm/valve inserted in the fuel hoses that I've not seen much info on. The inbound fuel hose attaches to a short bit of pipe on top of this thing, another short hose attaches it to the pump, a hose attaches the pump out line back to this part and a final bit of hose connects to the fuel filter and then to the carb.

I read a fuel cutoff was put in 1971/72 VWs but info seems scarce. The pump itself is an aftermarket sealed item and I'm wondering if this unidentified part is a fuel cutoff or pressure regulator added when the aftermarket fuel pump was replaced by a previous owner.

This bit adds a lot of complexity/difficulty to installing the fuel lines by requiring several really small sections. I'm not sure it's needed at all, looking at other VWs with aftermarket pumps. First, what is it? Second, is it critical? Third, can it be eliminated to simplify the hosing/installation?

Thanks!
Dave

[sjbartnik]

It's an anti-drainback valve.

Keeps fuel from draining back to tank. Earlier cars had these and then on later cars this function was built into the fuel pump, eliminating the need.
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1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[xvcs13]

Ah, thanks! Does that mean with the new EMPI pump I'm going to put in I don't need it?

[67rustavenger]

[xvcs13]

Thanks for that confirmation, much appreciated. This'll make the job a lot less tedious.

And yes, I'll keep it! And I'll look Bill's work.

Dave

[kreemoweet]

[FreeBug]

I've seen them mostly on twin carb type 3 engines, my 1500S had one. I've also heard it described as a vapor-lock solution?

[xvcs13]

Ok, that makes sense given I have a '71 and they put them on at least '71 and '72 as far as I've read. But what happened in '73 and beyond? Do they all get these added? And same for any pre-'71 that gets a new aftermarket pump?

[kreemoweet]

[mikedjames]

I have heard of upright engines with stock 34PICT-3 carburettors and leaking metering valves in the carburettors, but the usual problem is anything Weber....

Their needle valves rely on a tapered needle resting on the edge of a hole drilled in the valve. As the engine vibrates, a ring of wear appears and then the needle stops working 100% , the float chamber keeps on filling up, especially with a full tank of fuel.

So fuel shutoffs are needed with stock fuel pumps and Weber carburettors.

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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[xvcs13]

My Ghia doesn't have a Weber carbs, isn't an upright bus engine nor has other mods. Simply an aftermarket pump and the carb that came from the plant, a Solex 34PICT3.

From what I'm gathering is that it's probably needed in '71 and '72 type 1s--though one person said it wasn't. And probably for aftermarket pumps, regardless of year.

[kreemoweet]

The VW Solex carbureter needle valves are exactly as described above by mikedjames, and they have the same
wear and leakage problem, which is of course why VW used the cutoff valves. I have seen some very pronounced wear
rings on the needles from used VW carbs.
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