pain in the backside fuel leak

[marcusthemoose]

i broke down the other day due to the dreaded points giving out on the fuel pump. i have since renovated the points and have a fresh set to go on.
now however fuel has started leaking from the pump to float chamber pipe, right where the pipe joins the float chamber. thinking it was a dodgy pipe or clip, i replaced both, and it still poured out.
at the advice of mr haynes, my dad and i then took the float chamber lid off to check the float was ok, and there was no dirt in the jet. after reassembly all seemed fine, my dad putting it down as either dirt or ice even.
i have just come back from the Shell garage in town, and from the journey back, the damn things gone again. i know it was on the way back, as i checked in the station.

my question is, where to go next? the hose clips are plenty tight enough, and the pipe is a brand new layered type, rather the over braided old type. i am reluctant to drive it in this state, A, because its wasting so much fuel out of my tiny 5 gallon tank, and B, because the airflow will blow the leaking fuel back, in the direction of the hot exhaust!

any help is gratefully recieved so i can get her safely back driving.

[RobThomas]

HS type carb (flat topped float chamber)?
The overflow comes out where the pipe goes on so I'd be thinking float valve. If it has got some crud sat just above the valve or maybe a bit of old rubber stuck inside then that would do it. I also wonder if the flopping pipework would induce the pump to keep kicking over and overloading the valve in the chamber. If you turn the ignition on and give the pipe a shake, does it tick a bit more? (if you see what I'm thinking)
Lid off, pipe off, wash out, look at needle valve and seat for any sign of a wear ridge. Next thing on my list would be to see if the float height is correct and that the float is actually floating and not part filled with fuel.

Something to start with, anyhow.

Cheers

Rob
(Coming down to Dorset at the weekend, maybe. Sturminster Marshall)

[taupe]

Hi

Where is the fuel leaking from?

If its at the pipe joint on the float bowl it could be a cracked or loose pipe in the casting??

If not then probabl the float needle.

[marcusthemoose]

cheers guys, i'm pretty sure it is a problem with the float chamber. thing is, it never did this before the pump broke. its a bit nippy now, but theres something to do on saturday. i think the joint blows out to let the pressure escape. it is a flat topped float chamber.

put your thermals on rob, its bleedin nippy down yer.

[bmcecosse]

If you are sure it's not the pipe connection - then surely must be the float valve? Perhaps now the pump can actually pump as it should - it has revealed the weakness in the float valve! Certainly don't drive it with a fuel leak.........

[marcusthemoose]

now it is hopefully fixed. turned out a strip down of the needle valve and the pump revealed silt build up, especially in the valve in the pump, we think allowing fuel to leak back towards the tank, letting off the pressure, and the pump then pumping again, over loading the needle valve and then filling the float chamber to excess.

[bmcecosse]

Hmm - not convinced!

[marcusthemoose]

i have a new genuine su hs2 rebuild kit, including needle valve, gaskets etc. i also have a new set of points for the pump. at the first sniff of trouble these will be fitted, hopefully when its a little warmer. at the moment my attitude is leave well alone.

[bmcecosse]

As long as it's not leaking - I agree!