Join Date: Dec 2009
Location: Hobart Tasmania
Hanging revs problem, 75 Alfetta GT Webers
Does this symptom ring a bell with anybody?
My GT has a hanging-revs problem, but typically only during/after heavy throttle applications.
Revs will fall back OK under little or no load (not instantly, but OK) - eg revving while stationary, or lifting off from steady throttle, but when the throttle is loaded, for example when accelerating through the gears, revs take way too long to fall back; long enough to have to pause before slotting into the next gear, for example.
The problem SEEMS worse after the engine is fully warm.
The distributor is a new 123 unit
My Timing efforts have been checked by my Alfa guy
Much spraying of carb cleaner around the carbs doesn't indicate an air leak
Carbs are 40DCOEs 72&73 'emission' carbs, with standard jetting
Motor is unmodified as far as I know, certainly not valves etc, which have just been renewed, standard air filter.
Mixture screws are @ 4.5 turns out, below that it spits and farts
With careful balancing using a 4-tube vacuum gauge, adjusting air bleed screws to get under 1 HG (?) vacuum variance, the problem is lessened, but never goes away.
The shop who just performed the head rebuild do not have the balancer, I need to borrow it from elsewhere, and won't have access for a week or two.
Is this problem all about mixture and balance, or is something else at play?