Webber 45s with a cough

[silverian535]

Can anyone offer advice on a Ferriday tuned 2.1 pinto with a 285 cam and twin 45s?

It is great at full bore, but can cough petrol back through the carbs on a light throttle. Could it be ignition or even valve timing?

Presumably there are other examples of this type of setup that behave themselves.

Ian

[Moose.]

Are they relatively new Webers (last 5 years or so)? If so it's probably the progressive drillings. Apparently the Spanish build ones have the holes in slightly the wrong place which can cause them to spit back on very light throttle openings. I had the guy who rolling roaded mine to drill them out a little which helped, but didn't totally remove the problem.

[trackcar]

Spitting back on light throttle is usually a weak mixture problem so the progression off idle is probably the culprit? the answer above would seem to offer the cause?

[silverian535]

Thanks guys, I had thought that the cam timing might be too far advanced - could this be the issue? (it would be nice if it was just the carbs though)