I need some help!

I have a 1979 F250 with a 4.9l inline 6. After re-building the carburetor 3 months ago, replacing fuel pump and fuel filters two days ago I was driving through the Chesapeake Bay bridge tunnel (20 miles into trip) on my way North when my truck started to sputter and stalled. Yes, in the tunnel. It would start right back up but would only go another 20 or 30 feet before it stalled again. The fuel filter by the tank had sediment, but the filter (not stock) by the carb did not.

My questions are:

1. Any ideas as to what the problem could be?
2. Carb is a YFA, but not sure about what model, where is the best place to get a replacement?
3. Do I have any other options besides a Carter YFA without modifying the intake manifold?

Thank you in advance!

 

Assuming the engine is not starting, is it getting fuel?

Since the problem is unidentified, why are you interested in doing this?

I've heard of some people running an Autolite 1-barrel, but that's not much of an upgrade. I've also heard of some people using a 2-barrel to 1-barrel adapter, but it seems like a lot more trouble than it's worth.

 

Thank you for the reply.

 

FMC400,
Thank you for the reply.

After the truck stalls it will start right back up with no problem and will idle without any issues. It is when I start driving down the road when it starts to stall out on me again.

I still don't know what the problem is.

 

I will bet it is a fuel pump/filter issue, sounds like the pump is weak to me anyway. Might want to do a GPM test for the flow rate.

 

I agree. Also, the fact that there is sediment in the tank filter is really suspicious, even if you don't see it at the filter up front. Besides, that doesn't mean the sediment is not the problem. The sediment in the tank filter could be building up enough to impede fuel flow and stall the motor. In fact it makes sense that you would only see the sediment in the first filter and not the second, assuming the sediment is thick enough.

It's going to be too difficult to troubleshoot a potential fuel delivery issue when you know the tank is full of garbage. It introduces too many variables. Take the tank to a radiator shop to be cleaned, or replace the tank, then continue troubleshooting the problem. You'll also want to do what you can to clear out your fuel lines.

You wouldn't hang curtains on a broken window, right? It's the same principle.

 

I also agree on a fuel pressure test/ tank cleaning, etc. but I would also trace your fuel lines and ensure none are routed near the exhaust manifolds or any other high heat source. I've seen several vapor lock issues in the past with I6's due to fuel routing!

My 2c! :-)

 

Thank you very much for the responses. You guys are always a wealth of knowledge.

Since the fuel pump was new I kind of jumped to the conclusion that the carb was the problem. I am by no means a mechanic. I will definitely remove and clean the fuel tank as well as check the routing of the fuel lines and fuel pressure.