[Mgs] Weber carb info

[Matt Trebelhorn]

You say that the car runs on the acceleration circuit; you're having  
trouble on the idle and progression circuit.

Clean it again.  You don't need to worry about the accelerator/pump  
circuit.

Take out all the jets and shoot carb cleaner through all the internal  
passages; clean the jets individually.  Make sure the progression  
holes (in the carb throat, just at the edge of the throttle  
butterfly) are clear.

My bet would be a clogged jet or progression hole.

Matt


On 21 Oct, 2007, at 11:56 PM, Ed Woods wrote:

> List,
>
> Well, after removing, dismantling, cleaning, reassembling, and  
> reinstalling
> the Weber downdraft to my friend's '77 MGB, I can report no change in
> symptoms whatsoever. I found the carb to be relatively clean, with  
> only a
> skim of rusty sediment in the float chamber.
>
> Idle is still rough and irregular, rough enough to cause the oil  
> pressure
> gauge to fluctuate. Steady running still experiences missing at any  
> steady
> engine speed, parked or driving. It does appear to smooth out during
> acceleration, perhaps when the secondary is open.
>
> Present ignition system is the new, self containing Pertronix with  
> mating
> coil. Plugs and wiring are new. Compression is great and even.  
> Valves are
> set. Plugs are new.
>
> After years of sitting, enough to dry whatever was in the tank, I  
> added 5
> gallons of fresh fuel along with a carb cleaner.
>
> How can such a simple instrument behave this badly?
>
> Thoughts?
>
> Do I tell the guy to buy a new Weber? Is it the Weber? Do I spend a  
> day
> putting a pair of SU's on this thing as a test?
>
> TIA,
>
> Ed Woods
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