Accelerator pump on BBD carb problems

shadango

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Hey all..need some help ASAP
My son found the accelerator pump on our 2 BBL BBD carb (1980 Volare slant 6) "fold over" on itself about a year ago.....so he replaced it with one from a kit.....its red with a green cup.....just like the one that was in it. The carb had done well up til then, started stumbling off the line......the new acc pump fixed that.
Well, after it started stumbling again, he found it has once again "folded" on itself so he bought a new kit and replaced it.......worked great at first.....but then while TESTING today, the damn cup folded again....this cup is BLACK.
Someone suggested lubing the acc pump rubber.......he didnt...what kind of lube would you use for that? Seems like the gas would instantly wash out any kind of oil or grease....???? He is in the driveway now, 90 degrees, and frustrated. HELP!
 

XfbodyX

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You need to look at the problem from another direction.

If its happening and happening over and over id pull the carb and check the bore the itself and clean and dress with 1000 grit wet paper.

Have you checked the coarseness of the bore it moves in?
 

XfbodyX

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Another thing to consider is they roll over when dry, is the float level right, do you have to crank for a long time after it sits.

If you have to crank for a long time are you pumping the acc right away before the bowl is full and lubes the rubber.

Sounds like it could be catching a dry spot too. Do you happen to have the plunger set on the hole for the most travel?

Lastly, there are better pumps then others, is it the loose simple umbrella type or does it have a puck and a spring in it?
 
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Aspen500

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Kind of a repeat of what X wrote in the link. Is the pump you have leather? If so, oil it lightly when installing. of course the gas will wash the oil off but the oil gives it a good start. Note in the link it also says (as X said) the bore must be perfectly smooth, especially if the fuel you use has ethanol in it.

Just my experience only, I always had much better luck with the leather plungers vs the ones with the rubber like material.

Disregard the Quadrajet part of the link.

https://quadrajetparts.com/accelerator-pump-plunger-leather-length-p-1159.html
 

droptop

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Had the same problem until I put an electric fuel pump on to fill the empty carb bowl. Today’s gas is made for closed systems and it evaporates and dries out the acc pump. Let the pump work a few seconds before pumping the acc to set the choke.
 

shadango

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Thanks all!!!

He took another stab at installing and SO FAR it seems ok......

He DID have it set to full stroke....so he backed off some and says response is fine.

He is 20---so the "if some gas is good, more will make more power! comes into play....LOL

The leather one (pricey!!!) seems like and interesting way to go to try if THIS one gives out......it was almost TWO years, turns out, since he installed the last one.......he had said one......

He said the bore is smooth.....

Its a daily driver so it really doesnt have a chance to set long.....I have that issue in the Cuda....Eddie 650......sits a week and I have to crank a bit before starting to get gas back in the bowl etc.....but I always (out of habit) pumps three tomes FIRST. I may change my habit and crank FIRST, then stop, then pump, then crank......didnt think about how the acc pump bore would be empty after sitting.

So this is all great advice!!! Love this forum and the folks on it....Thanks!
 
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