fuelling issue

[james butler]

hi guys n gels,
i need some help and info diagnosing an issue on a misfuelling weber carb.
when its running it seems to only run with mixture screw wound all the way in and when i look into the top of the carb it seems to be just gobbing fuel into the carb pretty much like its overflowing in the float bowl.
I've checked the floats and they're a bit bent, tried bending them back into shape but i think new ones are going to be needed, the float needle valve is very worn to the point a small shoulder is visible and I'm pretty sure i going to be leaking fuel whether or not its fully closed.

as a result I'm pretty sure its going to be a combination of bent float and damaged needle letting too much fuel in so the carb bowl overflows and floods through the jets into the engine which is why it runs only with the mixture screw all the way in.
does this sound logical to you and is there anything else i should check for?
cheers
james

[big_wig_074]

sounds a good plan, get a rebuild kit, change all the gaskets and seals etc....take your time and measure the float gap.

[james butler]

cheers big wig,

measure the float gap.

i remember doing this ages ago but cant remember for the life of me how to do it could you give me any pointers?
i seem to remember a 5mm drill bit was involved checking the gap between float and highest point? although that could be utter pish and me confusing it with SU nonsense

[big_wig_074]

ill dig out the instructions I used for you

[big_wig_074]

good info here http://www.clubgti.com/showthread.php?1 ... eeded-ASAP

picture here http://www.google.co.uk/url?sa=i&rct=j& ... 6459723022

[james butler]

cheers big_wih_074 i will look into that.
gonna give the car the once over again Tuesday but ive got a feeling the return pipe may be blocked going back to the tank and fuel is being forced past the needle valve.
only one way to find out so we will see.

[Macc]

Tis i with above problem so thought id pop in and give some background to the problem.
Symptoms, best to start where it all began! Overheating on the way to James's, rad fan failure which led to thermostat failure, leading to water pump failure leading to inlet gasket cookery! (Domino effect over a two week period)
between that happening and now the choke cables been replaced with an MG one (still works as it should, just a bit stiff), throttle cable retaining clip was lost and sourced but its best guess where it went so ive gone for the "just enough" setting so its tight enough to pull lever all the way but not loose enough to fall out the "groove" (never anyone around to depress the pedal)
New gasket at float chamber, new float, new needle and valve, inlet manifold gasket replaced as was the rubber seal, new fuel hose from carb to vapour seperator and new vac hose from carb to airbox and dizzy to servo thing
At least one of the manifold bolts had worked its way loose and all four of the screws that sit atop float chamber were loose to the extent that i could see the thread!
Tightening all that up however made no difference, not even a bit! Rear venturi still sucking in air and dripping fuel down

[Macc]

right i think i had best post what happened the other day when James popped over!

Firstly he detached the vapour separator and connected a y piece which seemed to solve the dripping fuel issue but not the actual problem, turned out, right at the end to be the mix screw had caught on a bit of swarf making us believe it was all the way in, getting past that solved pretty much everything and the car was set back up nicely. Still got miner air leak through throttle "bar" but im in no hurry to dismantle that can of worms!

Still bloody over runs now and again when hot though!

[james butler]

float level was a bit high tho, do you still have a pic of how high the fuel level was before we moved the float tabs?
still can't believe that mixture screw

meanwhile if anyone has a good remedy for air leaks around the throttle spindle seals please let us know!
I'm using o rings in mine but we need a more permanent solution.

[Macc]

Best one I have!

[james butler]

unfortunately i cant see the picture but for other peoples benefit if the fuel level is higher than that hole in the float chamber in the picture your going to have issues.

to set up the float you need to have the float just touching the float needle ball bearing (not pushing it in!) and have a 7mm gap between the top of the float and the paper gasket/carb top half the floats bolted too.
if the fuel level gets too high it just gobs fuel straight out of the venturis into the engine causing a massively rich idle.