running issues idling

[robx1r]

i have a strange on and i cant wrap my head around it.

on the car it idles like pure dirt just bearly ticking over like its missing!
but when i disonnect the vacuum advance it purr's like a sex crazed supermodel.

any ideas?

[Brigsy]

Air leak is leaning off the mixture when disconnecting aei pipe

[robx1r]

yeah it is running rich with it connected but the mixture screw is all the way in and intact,
and the idle jet is clean

[tiff_lee]

When adjusting the mixture screw is there any change in the engine idle? i.e are you actually effecting the mixture when moving the screw

[robx1r]

no its not makin a difference at all

[tiff_lee]

Have you had the screw out to inspect it, I know you say it's intact but just checking but either way I would say the problem is definitely mixture related.

[robx1r]

[nate78]

has it just started doing this or has it always done it?

[tiff_lee]

It's been ages since i've tinkered with these carbs but if adjusting the screw is making no difference and the screw is good as you have proved surely it must be something with the fuel enrichment/mixture circuit?

[Jonny5]

Your mixture screw has got the tip snapped off.
It should look like this



Get a new one fitted and it should fix all your problems.