Weber Question

[Jip]

Greetings, Pelicans.
I haven't posted in a few years because,,,well, my '69 911T runs pretty good with 210,000 miles on it. Last summer a little hesitation started showing up while driving from idle to about 2200rpm. A little popping in the intake and some 'fluttering' in the exhaust. I'm being very general here as I overhauled these carburetors 5 years ago and thanks to this site I spent four days tuning them up so I have a little above average knowledge of how they work.
My question is,,,while measuring the accelerator pump output I get 5cc's. The book says 6 or 7cc's. While looking down the carburetor throat and pressing down on the throttle leever on the carb there is almost 1/4'' of movement downward before any gasoline squirts out of the nozzle. I screwed the 2 lock nuts on the accelerator pump shaft outward all the way, lengthening the pump shaft, as per book. Still 5cc's. Looking down between the carburetors I can see what I would call too much play(wear) at the point where the accelerator pump shaft pins into the accelerator pump leever on the main throttle shafts passing through the carbs. Should gasoline squirt out of the nozzles the instant I press the throttle down? Has the accelerator pump shaft reached its' point of no return or am I missing something? When I set up these carburetors 5 years ago I remember the accelerator pump discharge was around 7cc's.

'Cheers' Roadslayer

[1QuickS]

Take top cover off of carb and observe fuel in bowl directly above the inlet check valve for the accelerator pump. If the surface of the fuel is disturbed when you stroke the throttles then this shows the check valve isn't closing and letting fuel that should squirt out the nozzles bypass the check valve and back into the float well.

When I service Webers/Zeniths/Solexes I disassemble these valves, refresh the seat and install new balls to address this issue.

[Jip]

Well that would make perfect sense. Look for a little wave action on the surface of the gasoline. Sorry. Boat talk.
If the accelerator pump check valves are the problem would gasoline then begin to squirt the instant I move the throttle lever on the carburetor? Or is there a built in delay allowing the throttle plates to open a fraction before gasoline begins to squirt from the nozzles?

Thank you very much for your help, 1QuickS

'Cheers' Roadslayer

[1QuickS]

Accelerator squirt starts immediately. What you are looking for will be demonstrated best by a quick wide-open-throttle rotation of the throttles. Small & slow actuations will not report a leaky check valve as clearly as a rapid motion will. Small & slow actuations would bypass fuel without much squirt but these type of operations do not need much additional fuel for adequate mixture strength in a well jetted carburetor.

[Jip]

That might explain why I was getting ~.7cc's when I freshened up the carburetors five years ago. I was being more forceful with the throttle leever and now I am deliberately being gentle with the leever in an attempt to see exactly when gasoline begins to squirt from the nozzle. Therefore, the .5cc's instead of the .7 as before. Therefore this question.

And thank you again for your time and generosity, 1QuickS.

'Cheers' Roadslayer

Oh. And,,,uh,,,sorry about the decimal points. But then,,,you knew that.