Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

'75 Eldorado Q-jet Driver's mix screw no impact

<< < (2/3) > >>

old cars:
your spaying way too much carb cleaner to be a valid test. the carb can suck in the fumes at that rate

Benji808:
Ok, thanks for the tips! What are the dangers of using a brass float?

Windowed needle and seat…what does that mean, and how would it impact the potential gasket leak? I will retry the test with less spray.

Thanks for the tips- it’s my first rebuild so I appreciate the education!

Cliff Ruggles:
The factory went to a solid N/S assembly in the mid-1970's to help prevent drain-back. 

Brass floats do not spec out the same as nitrophyl and they can leak at the seems and sink.

I'll bet the kit had a windowed seat with a small hole in it.  This seemingly minor differences change the fuel level at the correct setting so you are starting somewhat out of spec so the issues could be fundamental simply from using the wrong parts in it.

Nothing mentioned about installing primary shaft bushings, how much play there?

Benji808:
Thank you for the explanation! I actually did not replace the seat (I'm assuming the seat is the brass-looking thing that screws in that the needle drops into)...it looked fine so I soaked it in chem dip and hoped that would be fine.

The primary shaft - that's the "throttle rod" that runs through the quadrajet and attaches to the smaller two throttle blades, right? If so, I think those bushings are where my issue lies. I didn't do anything to it, and they seem to open and close freely, but there is a  bit of play, and right there at the throttle arm/rod seems be the spot I get the most consistent reaction from spraying carb cleaner (see the earlier video), and the throttle side is also the one where the mixture screw doesn't seem to change anything.

Could bad bushings cause these three issues:  1) rough idle 2) engine jumps from carb spray 3) mix screw not having effect?

If so, do you sell a kit and instructions on how to do that? (I've watched a tutorial or two so I'm generally familiar, but want to make sure I have everything I need before I take it apart.)

It's really close to running in a way I am happy with...if I didn't know the mix screw was supposed to do something and the rich smell bugs my wife I would almost leave it alone, because it's starting and driving really nicely now.

Thank you for your help!!

Kenth:
I guess the check valve in fuel pump would prevent drainback?

Here is what Delco/Rochester says about the non-windowed inlet seat:

Navigation

[0] Message Index

[#] Next page

[*] Previous page