'71 350 C10 only firing when gas dumped into carb ...
 

:devil:

This is, so far, a month long issue and my longest yet with any classic i've had the pleasure of owning.
Background: '71 C10 lwb 350/th350, performer intake(spreadbore), eddy 1405 w/ spreadbore spacer, holley fuel regulator/gauge(set to 4.5lbs), HEI.

It has been a full-on-war. The other day I was taking a trip around the block when the motor bogged(immense power loss) about half way around the block. If I took my foot off the gas it would die. I fired it back up and forced the son a bit*h back to the garage by throttling it to keep it alive. I assumed it was the eddy 1405 since i've nothing but issues with it, even after the rebuild it's been inconsistent. Example: it has idled perfect one day and not worth a damn another day. The truck was dialed-in awesomely after the performer intake and carb swap, then these issues have been randomly plaguing the truck since.

I went out this morning to crank it up.. nothing. So I decided to put "ol faithful" the quadrajet back on. I removed the spacer and put the quad gasket(the thick heat insulating bad boy) back on and It fired right up, but died. Hmm.... tried to crank again, and nothing. I poured gas into the quad and it fired right up, burnt the gas up and died. Sh**. I removed the fuel filter and the regulator(i didn't need or use the regulator with the quad before tIhe swap), no go. BTW the fuel pressure reading is 7-9.

i feel I should mention I had NO issues while running the stock intake and quadrajet setup; it was a majestic enterprise.

I hate to sound like I'm about to throw in the towel, but i'm at my wits end. We are about to move and I'm grumbling at the possibility of having to pay to trailer it. The recent birth of my son has limited my garage time substancially - patience running thin to say the least.

Community, please save me!
Thanks in advance.

Re: '71 350 C10 only firing when gas dumped into carb ...
 

Possible fuel pump issue?

Re: '71 350 C10 only firing when gas dumped into carb ...
 

if the qjet has been sitting awhile it probley needs to be rebulit

Re: '71 350 C10 only firing when gas dumped into carb ...
 

Don't just rely on the fuel pressure gauge. Pull the fuel line off and see how much pumps into a small bucket or jar. Should be a strong shot and fill it fairly quickly.

Re: '71 350 C10 only firing when gas dumped into carb ...
 

Fuel is the only thing you are lacking of the 3 things needed, gas, air and spark.If you didn't need the regulator w/ the quadrajet, the e-carb should be fine.

You using an electric pump?

Check for fuel delivery as post 4 suggested. If you have good fuel delivery, and the thing keeps doing it's crapping out, you may need to pull the fuel sender. There's a strainer on the end of the pickup tube that can get plugged up, or collapse. You can either leave the strainer off, and run a good in line filter, and/or buy a strainer for one of the newer cars that uses an electric in tank pump, and clamp it over the end of the tube. I've done this before. I ask the parts store employee if I can look at all their strainers. I look for the longest one w/ the pump connection at the end. I cut that connection off that end, and clamp the rest of the strainer (sock) over the tube......

Re: '71 350 C10 only firing when gas dumped into carb ...
 

Great suggestions thanks! Im using a mechanical fuel pump.

Re: '71 350 C10 only firing when gas dumped into carb ...
 

Thinking as if I were in your shoes...

When it dies, I'd check the fuel level in the float bowl. Is it low? Is it normal?

If it's low, I'd look into why. Stuck needle? Lot flow from the pump?
If it's normal, clogged jet? Since it seems to affecting many operating aspects of the carburetor, I'd look at the mains.

What I find will determine the troubleshooting path to take.

Re: '71 350 C10 only firing when gas dumped into carb ...
 

It sure sounds like a fuel issue. I'd put a 95-99% probability that it's one of the pressure or flow issues mentioned earlier.

One other thought is water in the gas. Heavy rainstorm recently? Prankster? Any significant water added will make an ethanol and water mixture fall completely out of solution in the gas. And the remaining gasoline will have a couple of points lower octane.