weber carb fault ?

[holmes]

hi i have a webber carb fitted to my 8v golf syncro which was put on by the previous owner, the trouble iam having is that the car idles iratic, when iam driving the car seems fine if not a little rough, then after a while the car starts to jerk and it takes full throttle to keep the car from stalling. very annoying and slightly danderous when pulling across traffic[:0] please help i have had the car a week and have replaced everything i can think of. regards

[Chris S]

Have you tried cleaning out the float chamber/filter or removing the jets (1 at a time please)and blowing through them with an air line?
While it wont help now you could also fit/replace the small inline petrol filter in supply pipe which will help to prevent any dirt entering the carb in future.
but from what you say it sounds like the idle jet is partially & intermittently blocked with a spec of dirt, which will probably be sitting at the bottom of the jet tube, until the vacuum sucks it into the jet blocking it, when you stop the motor the vacuum dissipates and the muck falls off, till the next time you start the car and the process repeats it self.
btw, do you have a copy of the Haynes Weber Carburettor Manual nr 3288? or nr 4177 Carburettor Manual, they show a complete stripdown and rebuild on your Carb.

http://cgi.ebay.co.uk/CARBURETTORS-NEW-HAYNES-MANUAL-FORD-WEBER-SOLEX_W0QQitemZ300124922476QQihZ020QQcategoryZ29392QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[holmes]

hi chris, have found the problem the previous owner in his wisdom decided he would locate the fuel line that goes into the webber, by using an old jubilee clip screwed into the brake servo vacume pipe (the solid black one) hence when i accelerated the pipe would suck in air through this hole and make the car run like poo. but thankyou for your suggestions. regards darren

[Chris S]

So the last owner was a VW Main Dealer mechanic then was he? []

[holmes]

drove to work this morning and the problem returned although not as bad ok at slow speeds and pull away but put your foot down to go a bit faster and it feels restricted. bloody cars. loosing the will to live.[]

[Chris S]

Try some Carb cleaner it may possibly help, if not you will have to strip & clean it out.

[no such user]

What air filter are you using on the Weber?

If you’re not using the proper OE spec airbox and trunking etc then you might be getting carb icing – this would be especially prevalent if you’ve fitted a K&N-type filter. Icing could cause the symptons you’ve outlined above, even in the toasty warm weather we’ve been experiencing over the past few months.

[holmes]

hi i havent changed the airbox everything is standard as far as i know, i did notice that when the car is first started the fuel filter is mostly full of fuel, but after a few minutes this disapears down to a tricle, i was under the impression that it should always be half full is this the case? maybe i have a faulty fuel pump, is this a common fault. i have used a fuel cleaner today thinking it may clean the problem but to no avail. please help[][V]

[no such user]

There’s no fuel pump – the carb has to draw the fuel through from the tank – maybe the diaphram in the carb is shot, or alternatively, maybe there’s some junk in the tank pick up.

You could take off the fuel feed and blow it back using an air line.

Also I’ve come across a situation where someone’s fitted an additional in-line fuel filter – there should be only one, or that might screw up the fuel feed.

Whereabouts in the UK are you?

[holmes]

iam in chichester, there was 2 fuel filters but i removed one but it still has the problem. i thought the fuel feed pipe from the tank went to a pump then to a resevoir( all on the front of the engine) then into the carb? if not then what are these other chambers for?

[no such user]

Sorry, yes – lift pump on front of engine – I was thinking of anything with an injection motor, which needs an electric lift pump on the tank, as well as the electric pressure pump under the floor – neither of which are present in a std Golf Syncro.

The pump on the front of the engine might need replacing, but I’ve not heard of one failing before – maybe Chris will be able to shed some light….

[Chris S]

No they dont very often partially fail, you could always test the pump by removing the pump feed pipe at the carb end and placing it in a jam jar or similar, then turning the motor over on the starter motor to see if any petrol comes out, you could have an air leak between the tank/pump or pump/carb,
There maybe a gauze filter in the carb inlet pipe have a look if there is and if it is blocked.

[holmes]

i will have a look tonight do the fuel lines run under or in the car, so i can check those, i can’t remember.

[Chris S]

Under

[holmes]

i checked the fuel pump lastnight and it is in working order, so i used a foot pump and attatchment to blow through the fuel lines to the carb and the supply pipe from the tank, and this morning the car ran fine hoorah so hopefully it was just a blocked pipe “touch wood” (iam touching wood) will keep you up to date thanks. regards darren

[Author]

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