I have a 350 in my 53 f100 with a holley 4160 carb. A couple of weeks ago it started dying at intersections and did not want to idle. First checked the fuel pump and it was not putting out the right amount of pressure. So I put a new pump on and a new filter. Still had problems so I rebuilt the carb as I was seeing gas leaking around the bowl gasket. It has been running good but started dying again and not idle. I started it yesterday trying to diagnois the problem but it was running fine. Today I put in some gas treatment and was going to drive it and get some fresh gas but it will not idle and stay running in the driveway. I am at a loss and need some help. I wish I had my 54 f100 back with the 351 Windsor. I did not have any trouble with it. I have had issues with this 350 since I bought the truck.

 

How's the gas tank? Is it clean or full of rust and debris? Did you see any foreign junk in the carb or pump/filter when you replaced/rebuilt them? Are you sure you still have a fuel delivery problem or could it be ignition?

 

I did not see any debris when I rebuilt the carb. If it is ignition where would that be? I put in a new rotor, cap and coil in the distributer. I plan to replace the plugs and wires soon, but I don't think it would be a hit and a miss. I would think it would not want to idle or run all the time.

 

When its doing its thing about not wanting to idle, how does it run otherwise? How does it run if you rev it up, and under load while driving?

Can you give a little more information on not wanting to idle? When that it happening is the engine running smooth but just not idling, or does it feel like there is an engine missfire?

Sometimes you can actually hear the misfire if you stand next to the truck. Soemtimes you can hear a "snap" as the spark arcs to a ground. You might try getting a squirt bottle of water and misting it along the plug wires with the engine running (running and in gear is better so there is a load on the engine but make sure to really chock the truck well or better yet, have someone sitting inside the truck with their foot firmly on the brake......and don't stand in front of the truck while you do this)

Note: at night time you can sometimes see the arc.

Bobby

 

As long as I keep it reved up it runs fine. When I let off the gas it idles rough then quits running. I have to pump the gas as I try to start it again.

 

Have you checked for cracked or leaking vacuum lines? I would be looking for something simple initially.

 

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Did you check the fuel pressure AFTER you put on the new pump? Especially since the carb was leaking? I recently put a new fuel pump on a sbc and it had similar issues....the new pump was putting out 14 psi!!!!
For some reason the quality of new fuel pumps is not very good...

 

Fuel line crack free?

 

Is it running rich/flooding (any black smoke from the tailpipe)? If so, you might have a bad float, float level set incorrectly, or a bad needle valve. It might be worth it to pull the top of the carb to double check these.

 

Just a thought and maybe irrelevant but a friend runs two double pumpers on a cheby and he said everytime his car sits for any amount of time he has to pull the bowls and clean them.Upon fire up he automatically bends the float out of adjustment due to gumming and sticking.I second the float adjustment.

 

That is a pretty nice carb and easy to work on. Your problem sounds to me like float level or needle/seat problems. Here is a really good video on how to make that adjustment:

Good luck . . . hope the helps.

 

I had a vehicle that did the same thing. Finally found a vacuum line off. Check your vacuum lines or a vacuum port cap popped off. Good luck.

 

I agree, very possible with the recent work that either a vac hose didn't get put back, or got knocked off, cracked, etc. If it were a pressure-related problem it would likely get worse as rev's increased. If the carb was adjusted with a really low pressure from the pump, it may need to have float level reset, as pressure affects setting somewhat.

I wish all carbs were so easy to set!

 

I have checked all the vacuum lines and they are ok. I rechecked pump pressure and it is around 8 1/2 psi. I did notice it was wet around the accelerator pump gasket. I think it is starving for gas. I start it up and it will run fine for a few minutes then it will start to run rough then die. I am thinking I need to pull the carb off and pull the front bowl off. I think there is a needle or float problem.