Weber DFV carb trouble Options

[amphiduck]

Let me apologize now before anyone can make fun of me for having a single DFV carb setup on my '73 1.7.... Maybe someday in the future I'll man up and get dual carbs or even FI.

My problem is that the car idles fine, but when I stomp the accelerator, the car bogs down and loses RPMs. While idle, it takes a fair amount of bogging until it finally revs up. In gear, the car dies. My assumption is that the secondary valve in the carb isn't opening up and allowing more air in. I can't figure out how that valve even opens in the first place. I see the linkage and can open it by hand, but not through the accelerator pedal. Any suggestions?

Thanks ahead of time

[sean_v8_914]

linkage disables secondaries while choke is on or I should say it enables secondaries only while choke is open
...is this a new problem?

[euro911]

It's been a L O N G time since I had one those (on a '67 BUS), but kind of remember something hinkey about the linkage too.

Not that this is going to cure your current problem, but doesn't the secondary butterfly operate by intake manifold vacuum? (IMG:style_emoticons/default/confused24.gif)

[sean_v8_914]

it has a linkage from teh choke to the secondary, right? with a cam and latch.

[amphiduck]

Finally had another look at the carb, and it appears that the PO put a stronger throttle return spring on it that wouldn't allow the primary to link up with the secondary. Tried to do a home job and bend up another spring only to find that it is too weak and the engine races. Is there a website that sells factory elasticity springs for webers?

[amphiduck]

Or maybe an adjustment to the accelerator pedal for more throw is in line?

[jaxdream]

The only adjustment in the accelerator pedal is the link rod from it to the bellcrank on the peadl assembly, which isn't much of a lenghtening of shortening deal.You need to basically find out how much throttle cable movement fore and afat you have , length in inches / mm that the end moves , how much movement in the bellcrank on the carb , what length it takes to go from closed to wide open throttle. With this set of measurements try to figure out the attaching point of the cable to the carb that will give the amount of movement that you need . You have already figured this out , but it is sometimes a trial and error process involving things that PO do to cars (IMG:style_emoticons/default/screwy.gif) and waht we the current owner does (IMG:style_emoticons/default/sawzall-smiley.gif) (IMG:style_emoticons/default/ar15.gif) . Good luck , let us know what you come up with , as you are probably not the only one to use this carb setup here , not everybody is brave enough to admit it as you have been . I have three of these carbs in a box in the basement , I offered to another fella on the other forum , never heard back from him , if you need parts , I may be able to help with that . I haven't had any of these actually running on a vehicle , so I am not much help there .

Jack

[andys]

By your description, it sounds like the accelerator pump in the carb is not working properly. With the engine off, look down the carb and quickly open the throttle valves; you should see fuel squirt out of the discharge nozzle. If no fuel, then either the accelerator pump diaphram is bad, the check valve is stuck, or there's dirt in there clogging it up. It could also be that the transition jets are clogged. The secondary valve not opening would not result in the symptom you describe.

Andys