Stromberg 150 CD Carb Question

[stealthstylz]

Had a go at starting the Humber today after finally going and buying a funnel to put some petrol in. It turns over and begins to fire but as soon as you let go of the key it cuts out.

Fuel is then curse word out of a "plug" on the bottom of the float chamber. There is one big plug on each carb.

What would cause this leak? I've tried changing the plugs to see if the rubber seal was knackered but it made no difference.

I am thinking the needle valve is buggered or the floats have pinholed and flooded but i've no idea with this sort of carb.

Matt

[BenzBoy]

Are you sure it's coming from the bottom of the float chamber and not just dripping from there after pouring from (for example) the float chamber vent? I have a Stromberg 175 carb on my car and I think they're quite similar. Check there's no crud in the needle valve, and that the float armature is not sticking. If it's like mine it'll have a plastic float so you could check if the float is holed whilst you're checking the rest.

I had a leak caused by a small diaphragm splitting on mine. I'm unsure what the purpose of it is... maybe some kind of enrichment device... but it caused the fuel to drip off of the shut-off solenoid so it threw me for a while as to where it was leaking from.