Carb Issues

[jj72]

I have 500 cfm Holley 2V manual choke carb. I use non-ethanol gas and have had my tank cleaned and coated (4-5 years ago). I have replaced the fuel pump (6-7 years ago). I put a carb rebuild kit on (5-6 years ago). The question I have is - When I first start it up with the choke pulled, it starts right up. I let it warm up so that it will idle on its own. I can then drive it for 5-10 minutes before it wants to stumble and die (especially when at a stop sign). I can get it to start up and run a short distance before it dies again. I have to let it get cold before I try to start it again. It had been fine up until recently so I am wondering what the issue is.
Do I get a new carb?
Do I have someone professionally rebuild my carb?
Is it a fuel pump?
Is it a simple resetting on the existing carb?
Fresh new inline fuel filter?

 

[r4rabbitx]

Cold start fine, dies after warming up, runs again only when cooled.
Most likely causes: Fuel delivery issue (old pump, clogged filter, vapor lock) or carb heat-related problem.

Recommended steps:
Install a fresh inline fuel filter.
Check fuel pump pressure when hot.
Inspect for vapor lock or heat soak.
If still an issue, professionally rebuild the carb.
New carb only if rebuild doesn’t fix it.

 

[EPB72]

Problem at idle only ? Can you hold it off idle and under load runs ok if so ,,, when running bad ,choke out carb by placing hand over air horn or slowly closing choke plate and see if engine speeds up/ smooths out of does it run worse,/ loads up ,, If speeds up suspect a lean condition air/ vacuum leak ,which is what suspect But I’d diagnos condition before just throwing parts at it ,

 

[Chiclassics]

Start with adjusting idle mixture screw with half a turn out (allowing more gas). Its possible initially when you cold start it was enough but as engine warming up it might not be sufficient to keep it running. Also is yours manual or autimaic transmission, because if manual then you dont have any extra load at stop sign but automatic creates a little bit more load on engine causing it to need little bit more gas..

 

[73azbronco]

might be choke issue

 

[SteveL]

If you don't have a bunch of money in it swap it out for a non holley. If you want a 2v get a rebuilt 2100.

 

[nvrstuk]

Everything rabbit said above.

Carbs run when the engines hot. They don't care.

Check all the symptoms of no fuel to the carb after it shuts down.

Let us know

 

[Bruners4]

Correct fuel pressure and volume are critical to having a correctly tuned carburetor function as designed.
I would be checking these items when the carburetor is acting up. It may point to another area before the fuel pump that is the root cause of the issue.

 

[cldonley]

If you don't have a bunch of money in it swap it out for a non holley. If you want a 2v get a rebuilt 2100.

The 2100s are pretty bullet proof, but beware the "new" made in People's Republic ones. IMHO it's better to find an old one in the pick n pull and rebuild it.

 

[SteveL]

I run q-jets from jet performance

 

[jj72]

Drove Bronco yesterday. Drove around the neighborhood and then brought back to the garage and allowed to idle. Noticed that while idling that the inline filter was emptying with only some fuel dripping/dribbling into the filter. The lack of fuel finally starved the engine so that it stalled.
Is this an obvious need for a change in the mechanical fuel pump?
Some other points to make - The choke is manual to the 500 cfm Holley. The transmission is 3 speed standard. The vacuum line between the intake manifold and valve cover appeared to be sealed. When the engine was warm, I could pull the pcv valve which was connected to the vacuum line and the engine would want to stall. Once I reinstalled the pcv valve back in the valve cover the engine would pick back up again until it became fuel starved.

 

[NJBronk]

Could be the pump or maybe you're pulling air into the fuel lines somewhere?

 

[Chiclassics]

You have gas in float bowls...which when clears it opens up and lets gas in. Try installing a fuel pressure gauge in between to rule out fuel pump issue. Typically you should get 3-6PSI.
Mechanical fuel pumps do get bad...especially aftermarket ones and you are saying 5-6yrs so.

 

[SteveL]

Do you have braided fuel lines? If so look for swelling or squeeze down em every few inches and see if they leak. Had same thing going on in the inline filter. My buddy happened to. Bump the braided line going across the front and fuel came gushing out. The rubber line had rotted out but looked fine on the outside. I no longer run braided fuel lines.