1979 Ford F-150 302 Carb/fuel supply problem

Tiny
MANGOC
  • MEMBER
  • 1979 FORD F-150
  • V8
  • 2WD
  • MANUAL
  • 176,000 MILES
My truck won't start after it sits a few days. It starts very easily any other time. Starter fluid fires it up immediately, but usually takes several repeated squirts before it finds enough gas to keep running. Pouring gas in the carb may help, but it isn't an instant cure.

This has been a problem for years now. I've replaced the mechanical fuel pump and filter. Everything is original on the truck, no rebuilds. The pollution control equipment/hoses are removed or plugged. It has two gas tanks but I only use one and keep it low because it will leak if filled to the top.
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Thursday, November 12th, 2009 AT 9:34 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
I have a couple questions. Have you ever checked engine compression? Also, is the pump run from a lobe on the cam?

Let me know.

Joe
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Thursday, November 19th, 2009 AT 9:32 AM
Tiny
MANGOC
  • MEMBER
I've never tested the compression. After 30 years and 176K miles, I assume it's low

The fuel pump mounts on the engine block and runs off some kind of lobe, but I don't remember if that's the camshaft or something else. I replaced it on general principles more than two years ago. I didn't notice any change.

Thanks,
Scott
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Thursday, November 19th, 2009 AT 11:28 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Does the truck run good any time? I believe the pump runs off the cam lobe. If it is worn, you're not going to get the fuel you need. Have you checked it for volumn?
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Thursday, November 19th, 2009 AT 11:59 AM
Tiny
MANGOC
  • MEMBER
It runs fine when it gets started, and never gives any problem after that. I can let it sit for a couple of days without problem, but if I go longer I will have a hard time starting it.

When I changed the pump a couple of years ago in California I was experiencing brief cutouts on long low hills. I haven't seen that happen since then, but I'm not sure if it was due the pump or changing my timing. I changed the timing, put premium fuel in it, and drove it back heavily loaded over the Sierras and Rockies without any further problem. Until I did that it didn't look like it would make it over the Sierras.

I wouldn't know about the volume of the pump supply. It had the same starting problem in California before I changed the pump, but I was starting it much more frequently then.

Come to think of it, I probably have never changed the timing, but I'm running mid-grade 10% ethanol in it now, the cheapest fuel we have here in Iowa, cheaper than low octane.
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Thursday, November 19th, 2009 AT 12:43 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
The only thing I can think of then is either the carb is leaking down so there isn't enough fuel in the float bowl or there is a problem with the choke. I need you to check something. THe next time you let it sit, kick the throttle to the floor but don't start it. Take off the top of the air filter and check to see how far the choke butterfly has closed.

Let me know what you find.
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Thursday, November 19th, 2009 AT 1:04 PM

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