Weber 40 carbs

[Bullman]

Ignition timing checked and set at 14 degrees, carbs balanced ,mixture set using a colour tune.Carbs are spitting on acceloration ,fuel is coming out of the bellmouths dropping on to the battery,fioat level set at 12mm.Anyone got any ideas is it a jetting problem,Ihave changed the cam 234 to 244,I do not remember fuel leaking when running the 234.1989 Supersprint.Thanks BULLMAN. p.s THANKS Rigs, Bricol,Eric,SteveGilbert,Ellie Boone,John Whyman for previous advice.

 

Bullman

[John Whyman]

From previous advice I got from those in the know (R.King etc)on Blatchat, you may have an overfuelling situation. The floats in the 40,s take about 4psi and on my car (1990 1700ss)the pump (facet interupter)was pushing out about 6 psi. Cure was to fit an adjustable in line pressure regulator (10 min job)set at 3 psi. no further trouble.I may have suggested this previously, but if you haven't got one its a worthwhile investment. I bought a Facet adjustable for £18.00.

 

Hope you find the cure soon. Happy Motoring. C7 WJW.

 

Edited by - John Whyman on 2 May 2001 00:28:57

[oilyhands]

If you are spilling fuel then you may have a fuel level / pressure problem. constant spitting can eject fuel from the bellmouths so the first thing to do is to check for excessive fuel pressure, if the carbs are brimming or flooding then you cant calibrate them properly.

 

A good test for excessive pressure is to let the engine idle with the air filter off, look down the barrels of the carbs and see if you can spot any fuel dripping from the aux vents, at idle there should be very little fuel around , if it is puddling or dripping then you have a problem with fuel pressure or needle valve sealing. Correct this first, if its pressure then do as suggested above, get yourself a good pressure regulator set at about 3 PSI, if its the needle valves..(inspect them for wear ridges) then repalce them.

 

Once this is done, if the carbs still spit then it will be weak progression or an air leak, the progression is governed by the idle circuit which may well need a larger/richer jet, if it spits under sustained accleration then the main circuit may be weak.

 

I doubt that its caused by timing, 14 degrees is adequate for a 244, the engine might be able to tolerate a degree of two more but this may push maximum advance beyond recommendations.

 

Oily

[Robster]

One quick fix that has worked in the past...the from air filter can collect a lot of insects and sh..t...blocking it up, I have found that when the filter is washed in petrol..or even brushed clean it is not nearly so bad. Worth a go!

[Robster]

That should say 'front' air filter..sorry!