help! 72 302 wont idle more than 10 seconds

[hyena429]

Well what i would do...Is hook a burp tank up to the carb and gravity feed your carb..If it starts up and runs well..You know it is still soming in your fuel system....gravity fed tank eliminates your fuel system..Take the normal fuel line and run it into a bucket and watch out much gas "if any" It pumps out while runing.

pretty much what i did below on a old mustang 2 below....just to get it runing..cause the tank was full of nasty stuff..I made a burp tank out of a radiator fluid bottle..and hung it up high and away from the car incase something happend...Bipassed all the fuel system...So if it keeps dieing in 10 min..You know it is something more than your fuel system..this will take it all out of the equation..cheaply too..without ripping your fuel system apart.




Ohh does sound a bit like a vac leak...Better get a vac gage on her..Almost sounds like a vacum advance problem.

 

[rutkak]

no doubt in my mind, it's a vac leak.

 

[judge]

I didn't notice what ignition system you are running. But I use OEM style components. I've had the ignition condenser fail and result I'm the same symptoms. BTW replace the points also, condenser failure causes them to pit badly. Filing the points can get you about ten minutes of run time if you're stranded.

 

[Gonzo1970]

Mechanic musta fixed it..

-Gonz

 

[mcampbell26915]

Hey after a long winter I'm startin to work on my mustang again, im having the same problem I had before winter hit, I tried starting it today and there are 2 problems that I see. One is that my battery doesn't seem to hold a charge at all, I charge it all the way and then it lasts for maybe 45 seconds total of cranking , but when I bring it to autozone it tests ok, idk why that would be. I figured I'll just get a new battery anyway, but that's not the main problem. The 2nd and main problem I've been having is that whenever I depress the throttle , no gas squirts into the carb. It used to work and I could hear feel and see the gas squirting into the carb and venturi when I depressed the throttle arm, but recently ( as in today and about a month before winter) it hasn't been working at all. When I depress the throttle arm now I can only hear air going into the carb, there is much less resistance also when pushing down on it ( its a lot easier to depress it now). It feels and looks and sounds like absolutely nothing is being squirted into the carb, but the filter is new, and the carb is newish, and the fuel pump is new. I tried using a generous amount of carb cleaner to get it to start for just a moment but it didn't start that way either, but I beleive this is because the battery wasn't good enough to crank it hard enough or long enough to start it after the winter. I'll start with a new battery , but I know that won't solve the problem with the gas , any thoughts or ideas would be greatly appreciated I really wanna get this thing running for spring. Thank you

 

[MechEng]

I'd put one if the clear inline fuel filters on your fuel line. It sounds like gas might not be making it to your carb and this would let you see visually if that's true or not

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[Jeff73Mach1]

are your fuel lines from the pump to carp and pump to tank reversed?

 

[matrixx]

There's so many issues that could be at play here. A weird battery can cause all sorts of issues. How old is your carb? Has it been rebuilt. The accelerator pump diaphragm could be blown and not working hence no gas squirting into the engine.

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[Paul of MO]

I had a car that would idle for 10 secs or so then die - it would restart just fine but then die again.

Turned out to be a weak rubber fuel line from the fuel sender to the hard fuel line back by the tank along with little or no tank venting.

The soft line would get sucked flat by the fuel pump shutting off the fuel, the car would stall, the pump would stop and the line would open back up letting the fuel flow again.

That was fun to figure out.

- Paul

 

[judge]

That's good information Paul. I'll remember that one. I would remove the top of the carb and put the eye on the fuel. I'm guessing there is none. That will direct the next steps. On the two barrel that's about 6 screws and the big air cleaner stud and choke linkage to remove the top. No fuel: line issue, filter, pickup or fuel pump and don't over look the needle and seat. If you have fuel carb blockages mentioned by others and rubber valves also mentioned. But you need to see if fuel is the bowl. Then move in one direction from there. This new fuel can cause some rubber to soften and create issues in carb and line connectors.

 

[CZ-75]

Also, regarding the battery... A bad battery can read OK on a tester until it is put under a load. I had a battery that kept reading OK at the auto parts store, but wouldn't hold a charge. My mechanic buddy put a load test on it and it failed. The load trest creates a short, and measures the power while shorted. A bad battery will fail this test quickly, as may be the case with yours only providing 45 seconds of cranking.

 

[TommyK]

If the car has sat all winter and you have only been able to crank it for 45 seconds or so due to the battery issue, chances are you have no fuel in the fuel bowl. Get the battery straightened out and try it again. If you feel comfortable with it you can prime the carb by filling the fuel bowl through the vent. I use one of those baby snot suckers to do this.

 

[Jeff73Mach1]

I fill fuel bowls with a piece of rubber hose pressed over the vents and fed up into a small funnel a jigger full of fuel into each one is usually plenty.

You can also hold a rag dampened with gas over the carb and get enough fuel into the system for it to fire over-but a backfire will light you up.