Freshly rebuilt quadrajet flooding from top of carb

[Cliff Ruggles]

Are you still using .036" primary metering rods?

Did you install an external APT screw in the baseplate?

[gregcarter]

The Edelbrock 1902 comes with a horizontal adjusting screw between the idle mixture screws for the base adjustment for the  APT.
The metering rods are .036, jets are .069.
Thanks,
Greg

[gregcarter]

I may have mentioned before, that I set the APT screw to slightly raise the power valve because I had no base setting because there was a bunch of gooey stuff in there and the screw was very difficult to remove when disassembling.

I can push the power valve down when the engine is off, and I can feel that it is down at idle with a small piece of aluminum tubing.

G. Carter

[Cliff Ruggles]

With .036" metering rods in .069" jets you are too rich and not going to have any control with the APT screw in the baseplate.

Edelbrock found themselves using that jet/rod combination because they left out the lower MAB's in the main casting on the production line.....Cliff

[gregcarter]

I'm guessing I'll order .040 rods?, Do the .069 jets sound adequate?
G. Carter

[Cliff Ruggles]

When you get time call the shop and I'll set you up with some metering rods that will work.....Cliff

[gregcarter]

Thank you Cliff for the jet needles. I installed them and I will test the cruise mixture on the freeway on Monday.

Unfortunately my idle is still stinky rich with no adjustment on the idle screws. The more I think about it, the more I think that this carb has always had a super rich idle since I bought it.

I had changed to .035 idle tubes but went back to .032 after still having a rich stinky idle. By the way, your new .032 tube collars are .060, not .061 like the old collars, they slid right in and popped out when I blew air through the main jet.

Anyhow, running the motor at a low idle, maybe 500 rpm, I backed out the idle screw until it was loose, and rotated the primary shaft. it closed a little more, and the rpm dropped about 50 rpm but did not stall. I ran the mixture screws in and out, and watched my O2 sensor read over .9 volt the entire time.

In the forum, I saw a few ways to address this problem, looking for nozzle drip, wrong gasket etc. Well, I finally used a flashlight and saw a drip on the passenger side, about a 1 drop every ten seconds or so. The driver side was dry.

My O2 sensor is on the driver side, and it is a split manifold with no connection so the richness on the right side wouldn't show up on the meter. The drip is not the original problem of overrichness

I am going to check the bottom gasket tomorrow and see if the bypass holes line up.

In the mean time, I am hoping that Cliff can recommend opening up the bypass holes to a larger size, and what size?

Here are the current specs:

idle tubes                                .032

idle channel restriction              a .043 drill fit, a .052 did not
                                               don't know where the inbetween bits are

upper idle air bleed                    .070

lower idle air bleed                    .062

idle bypass air                          .039

mixture screw holes                  .081

main air bleeds  (horn)              .042

main air bleed (body)                .042

main well bleed tubes                .025

secondary well tubes                 .070

main jets                                 .069

rods                                        .042

sec rods                                  DR

float                                       1/4 inch

Thanks ahead,
G. Carter

[gregcarter]

Ok, I'm dumb. I just looked at the manifold and both sides of the manifold feed both sides of the motor, so my O2 sensor is picking up the drip.


I am going to check the bottom gasket tomorrow (no, it is not one of yours, and I'm sorry)and see if the bypass holes line up.

If the don't line up, ( I did check them last Friday night, but my eyes could have been tricking me. One hole lined up, the other, I'm not quite positive), I'll cut the gasket larger.

Thanks ahead,
G. Carter

[Cliff Ruggles]

Probably ought to check the other gaskets as well.  Doesn't sound like you ever got a kit from us, so they may not be the correct gaskets either.....Cliff

[gregcarter]

You just sold me the top gasket last week, I have your accelerator pump, and needle and seat in there, as well as 4 mabs, 2 idle tubes, and a atp screw, and new bushings. The only thing I can think of that isn't yours is the base gasket, and the throttle body gasket, which looks like an excellent quality gasket, just possibly with a slightly offset hole.
gc

[gregcarter]

Ok, I removed the throttle body and saw that full manifold vacuum was being applied to the bypass opening in the carb body from a cutout in the base gasket. Whoops......
You are correct once again. I need the right gasket. I better order your float as well, and any other part you can think of. The list of your parts I have is above on the previous post.
I'll call you in the morning.
Thanks for your help,
G. Carter
Edelbrock 1902

[gregcarter]

Thanks for the gasket.
I should have ordered a base gasket as well, just to make sure it was right, as it looks like there are more than 1 style.
The one I used has a flat area at the front that covers but does not seal the area of the pcv vacuum inlet. My other base gasket is open in this area and seemed wrong.
The motor ran a lot better with the new throttle body gasket, but I still did not have mixture screw control.
I poked around the secondaries, stalling the motor just by tapping the air valve, so I thought there might be some unwanted vacuum in there, so I removed the throttle body and detected small particles of dirt holding the secodaries open slightly. (I drive on dirty construction sites).
I cleaned and reindexed the plates and reinstalled the carb, sealed the airbox and now have control with the mixture screws.
So off to the smog shop I go.
I'll let you know if it passes.
G. Carter

[gregcarter]

Ain't over yet.
Drove the truck to work (50 miles), seemed like the idle was low, so I raised it up a little and the stink and rough running was back.
I turned in the idle screws all the way, the idle came up, it stank, so I drove it home.
I looked down the primary side and it was dripping, tapped the air valve and it stalled. Looked down the secondaries and they looked clean
I opened the air valves and secondary vaives and sprayed cleaner around, and started the motor.
Wouldn't run 'til I opened the idle screws, so I set them and lowered the idle.
Open the air valves all the way, and the idle stayed almost the same, I think it dropped a little.
The secondaries must not be sealing all the time.
They looked and felt perfect when I had them apart yesterday.
I'm detailing out my air intake system, I can't think of any other thing to do.
Gregory Carter

[gregcarter]

Here's another dumb one.... the air filter was too short allowing dirty air over the top into the nice clean carb.
Took care of that and took it to the smog shop.
Failed on nox, probably carbon buildup, egr blocked(which it is) dirty catalytic converter, or running hot. I'll work on these.
The smog tech said he thought the carburetor  was working fine, even though I was getting a little choked up on fumes in his small shop.
That's all for now.
G. Carter

[gregcarter]

Took off the manifold, and cleaned the egr passage, reassembled it all, and took it to the smog shop and it passed finally.