1980 QuadraJet issues

[Ron Dame]

Thea has 68,000 miles, and generally runs well. Cold starting, however, is an issue, as it's always flooded, even after a week of not driving. Why do I know it's flooded? because if you don't hold the throttle at least 1/2 open, or god forbid, pump the gas, it'll be a while before she finally fires and belches black smoke. Even so, it takes a few moments for all cylinders to fire and there is still some black smoke. Once she's cleared her throat, she runs perfect. Plugs are clean, too.

First, it's not the choke, as I've left it blocked open and on even chilly mornings, it did the same thing.

While a kit is a reasonable start, what areas should I pay special attention to?

[mfg]

3 hours ago, Ron Dame said:

Thea has 68,000 miles, and generally runs well. Cold starting, however, is an issue, as it's always flooded, even after a week of not driving. Why do I know it's flooded? because if you don't hold the throttle at least 1/2 open, or god forbid, pump the gas, it'll be a while before she finally fires and belches black smoke. Even so, it takes a few moments for all cylinders to fire and there is still some black smoke. Once she's cleared her throat, she runs perfect. Plugs are clean, too.

First, it's not the choke, as I've left it blocked open and on even chilly mornings, it did the same thing.

While a kit is a reasonable start, what areas should I pay special attention to?

If your Q-Jet has a composite float, it could be starting to sink due to fuel saturation… I believe a carb overhaul with a new float thrown in is in order here.

When carb is apart, the well plugs at the bottom of float chamber should be checked, as fuel leakage past those plugs has always been a chronic problem with this type of carburetor.

Edited Tuesday at 10:58 PM by mfg
Spell.

[Ron Dame]

27 minutes ago, mfg said:

If your Q-Jet has a composite float, it could be starting to sink due to fuel saturation… I believe a carb overhaul with a new float thrown in is in order here.

When carb is apart, the well plugs at the bottom of float chamber should be checked, as fuel leakage past those plugs has always been a chronic problem with this type of carburetor.

Thanks, that makes sense. I also saw where the well plugs could be an issue, but the post discouraged JB Weld, or similar because heat deltas would cause the plugs to leak again. But no alternatives were given. Do you have an idea?

[ronmanfredi]

4 hours ago, Ron Dame said:

Thea has 68,000 miles, and generally runs well. Cold starting, however, is an issue, as it's always flooded, even after a week of not driving. Why do I know it's flooded? because if you don't hold the throttle at least 1/2 open, or god forbid, pump the gas, it'll be a while before she finally fires and belches black smoke. Even so, it takes a few moments for all cylinders to fire and there is still some black smoke. Once she's cleared her throat, she runs perfect. Plugs are clean, too.

First, it's not the choke, as I've left it blocked open and on even chilly mornings, it did the same thing.

While a kit is a reasonable start, what areas should I pay special attention to?

Your carb is leaking at the well plugs and the float is iffy if stock.  You can get all the parts that you need for your carb model at:  https://quadrajetpower.com/

This Texas based company only offer service and parts on Qjets.  You can supply them with the carb #, which is on the main body of the carb and they can send you whatever parts you need exactly for your carb.  You can also call them for help.

[mfg]

J B Weld offers a higher intensity (stronger?) version that does a pretty good job.. but still iffy!

Some techs have drilled out the plugs, tapped the holes, and then screwed in small brass plugs… I’ve never done this, so I really can’t offer insight on the level of difficulty.

[Ron Dame]

Thanks ronmanfredi and MFG. I hope to get the carb number and order the kit later this week, then I can deal with this. I really appreciate the insight!

[WayneC]

I have rebuilt quadrojet carburetors in the past (I'm too old now), and I sent one to Recarbco in Pittsburgh CA that came back looking like it just left the factory (and performed like it too).

Recarbco is on Facebook (I am not). Not cheap, but excellent work/result.

[mfg]

18 minutes ago, WayneC said:

I have rebuilt quadrojet carburetors in the past (I'm too old now), and I sent one to Recarbco in Pittsburgh CA that came back looking like it just left the factory (and performed like it too).

Recarbco is on Facebook (I am not). Not cheap, but excellent work/result.

That carburetor looks WAY too good to even put on an engine!!! BEAUTIFUL!!

[Zedman]

Hi All- As an aside whilst this thread is open... I have a 1981 EME Carb that I'd like to replace with an un-ECU controlled Quadrajet someday.  Would somebody mind putting up what Carb Code numbers might be a good idea for substitution.  BTW if I do go down this route , the AIR Injection system and Catalytic converter will also be gone too. Charcoal Canister will be staying , however.   Thanks...

 

[mfg]

15 minutes ago, Zedman said:

Hi All- As an aside whilst this thread is open... I have a 1981 EME Carb that I'd like to replace with an un-ECU controlled Quadrajet someday.  Would somebody mind putting up what Carb Code numbers might be a good idea for substitution.  BTW if I do go down this route , the AIR Injection system and Catalytic converter will also be gone too. Charcoal Canister will be staying , however.   Thanks...

 

That is EXACTLY what I did on my ‘83 Avanti when I had had enough of the ‘computer command control’ system!

I ordered a non computer controlled Q-Jet for a ‘78 Impala 350… and also a non computer controlled distributor for same.(distributor has vacuum dash pot)

I made this conversion on my Avanti over 15 years ago… and have never looked back!

And yes, a true dual exhaust system, ‘68 Avanti ll style, also went on!!