Hey all,

I recently got back to driving my 76 F250 in the last week while I'm home for the holidays, and I'm having a problem with fuel starvation that I can't really troubleshoot.

I've always had issues with starvation during heavy load conditions, and I attributed that to the stock single barrel carb on the 300 six. Since I started driving again, the cutting out/starvation issue is presenting itself during normal driving, like trying to accelerate on to the highway. My first thought was the fuel filter, so I replaced an inline filter I added before the fuel pump. No dice. Now, my fuel pump is the style with the sediment filter on the top, but the pump itself was new about 1000 miles ago. Then there is the filter that screws into the carb.

I'm not sure if it's possible to get the sediment filter by itself (local NAPA doesn't list a separate part), and before I replace the carb filter I wanted to get some advice. Mainly, if a clogged filter would cause an intermittent problem like this, or if I should be looking into rebuilding the carb (a job that I didn't do even after the truck sat for 10 years before I purchased it). Since this rig sits for 4-5 months at a time while I'm at school, I started thinking it may be something gummed up in the carb but I'm not sure.


Thanks
Jameson

 

Definitely replace the filters - this is classic fuel starvation. My Chrysler Valiant had exactly the same symptoms; starving at heavy load followed by lack of power in day to day driving after it was laid up. Filters fixed it.

While you're at it I'd at least check the float bowl to make sure its not gummed up. A quick spray of carb cleaner through the small orifices should help even if it appears fine.

If filters dont fix it check your spark, although if it starts fine thats probably not the issue.

Cheers - boingk

 

You can disconnect the line from the fuel pump to the carburetor to check the flow. The service manual says that it should deliver 1 pint in 20 seconds. If it doesn't it could be a bad pump, a congested filter, or an air leak in a rubber hose or connection further back toward the tank.
You can test the carburetor filter by removing it and blowing through it. If it's clean there will be little resistance. If there is resistance replace it. If your pump filter looks like this:


And your carburetor filter looks like this:

You can buy them at Rock Auto for about $10 or so.

But what you are thinking is fuel starvation could be something else. Try to do adequate troubleshooting before replacing good parts and doing a lot of work that isn't needed.

 

If its during acceleration, it could be the filters, but I vote a carb rebuild is in order. Its not very expensive or difficult if you can find a good writeup or manual.