Solex 34 PDSIT fuel overflow

[melvin]

Hi all,
Does anyone know what this pipe is and why fuel might be pissing out of it on a hot engine?
Long story short, I went for an hours drive, stopped for a coffee for an hour then the van wouldn't start, popped open the hatch, smelt fuely. Took off the air filters to see fuel pouring out of the said tube on both carbs. It carried on coming out with the ignition off for about a minute or so.
Went and had another coffee to wait for the engine to cool and for the fuel to evaporate and after several cranks, she fired up again
It's a standard CU Aircooled, which to be fair is running like a bag of spanners at the moment, just wondering to why fuel might have been coming out of this tube in such quantity?

Cheers in advance
Long term quiet member Melvin

[CJH]

I'm not familiar with this carb, but on the Pierburg 2E3 that's fitted to the DG, there's a pipe like that that squirts fuel from the accelerator pump. When the throttle is pressed a small volume of fuel is pumped through this nozzle to help initial acceleration - see here.



The pump consists of a diaphragm and spring operated by a cam on the throttle spindle. If this isn't set up correctly, or the spring or diaphragm are faulty, then you'll get a flat spot when accelerating.

This isn't a valve, it's a pump - fuel will squirt from this pipe briefly as the throttle pedal is depressed, but will stop when the throttle stops moving. If this pipe has the same function on your carb then I'd be suspicious that it's passing fuel when the throttle isn't being depressed. It might mean a faulty diaphragm or spring in the pump mechanism. This would certainly contribute to poor throttle response with a marked flat spot. I would imagine that the diaphragm is part of a rebuild kit.

[CJH]

The diaphragm is part number 12:

[Markpc]

The needle valve will either be jammed open with dirt or the float isn't working. Causing the carb to flood.
Parts 23 and 26 in the previous post picture.
When the engine is running, it'll be running really rich and this'll be why it's rough. When the engine's off you'll get petrol leaking down the barrel and into the oil. So you might want to do an oil change too as the fuel will thin the oil and it won't do it's job properly.

All easy fixes.

[Markpc]

What petrol pump have you got? It could be it's pumping too much pressure which the needles can't control

[melvin]

Cheers for your replies guys!
The pump is electric, not sure what one though.
I initially thought was what Markpc said and that this might be some sort of overflow in case of such situations where the float stick and the fuel needs somewhere to go.
The old mini's used to just wee it all over the floor (nice and safe)
When I get home from work I'll check it again now the engine is cold to see if it is still pouring from the tube. I knida hope that it is so I can try and fix the problem.

MELVIN