Quadrajet Accelerator Pump Issue
 

I have been fighting an issue with my Quadrajet on my 74 GTO. It is very hard to start the car when it has sat overnight. The car runs and performs great when it finally starts and will start the rest of the day easily. I initially thought that the bowl plugs may be leaking overnight, causing it to be hard to start. However, I have had the top off of the carb multiple times and it will have plenty of fuel in it. I can look down primaries and the accelerator pump shot seems very weak to me. One side just barely dribbles out fuel. I have swapped out accelerator pumps twice. The pumps that I have replaced look normal upon removing them. Does anyone have any suggestions as to what I might take a look at to fix the issue? I am running out of ideas. Thanks

Call Cliff.......

Is the check ball in place? I had a problem with a flat spot once and it turned out to be one of the squirt holes had some casting flash so I cleaned it out with a torch tip cleaner.

As stated above it sounds like the passages have residual crap in them and are restricted.

Have you already gotten a good accelerator pump from Cliff? If you've not, do that first. Do your current pumps have garter springs or no?

Is the pump bore nice and smooth? If not, polish it with some 600grit sandpaper or get a hone and make it nice and shiny.

Confirm the checkball under the screw is installed, and get an extra one. Take a drift and using the old checkball, coin the seat a couple times, then discard the ball, replacing it with the extra one.

After that, work the pump a few times after filling the bore with fuel or fluid. You should see two streams of fuel coming up the passages. If both sides do not force quite a bit of fuel as you work the pump, then you're going to need to drill out the plugs and run a drill bit thru the drilled passages to clear whatever the debris is. You can re-plug the holes with small lead balls or tap the holes for set screws.

If you DO have good flow thru those two holes in the float bowl, then you need to check the corresponding orifices in the airhorn, making sure you have the correct gasket, while you're at it.

I can help with parts if need be, or else Cliff still deals in parts on his webpage. He can be difficult to get in touch with for tech support. He's kinda getting close to hanging it up, I think.