looking for help with fuel

[70Custom10Nut]

Not sure exactly where to post this question. I posted my question in the engine forum, so I won't go into great detail. My truck is hesitating at hiway speeds, amongst other things. I'm just asking for advice on what to look for. thanks, Cnut

[71meangreenc10]

If your going to check the fuel
1. see if trash (rust) is getting up to your carb.
2. check the condition of the carb, if its 40 years old, probably way past its time for a rebuild.
3. Whats the condition of the fuel pump?
4. Any vaccum leaks?

Dont forget to check the ignition system, are you running points or HEI? How old are the plug wires?

Smitty

[fdbdw]

X2 with 71 meengreen,

also check the fuel pick up sock, they get brittle and break up with age then the little pieces of sock get pulled into the fuel line
Also if you have an adjustable vac can on your dizzy make sure its adjusted right,
There are alot of things that can cause hesitations, always check the cheap and easy ones first, good luck and keep us posted

[gonzo6869]

Had a similar problem. I changed the fuel sending unit sock, did not change a thing, but was old and needed to be replaced anyways. Next I checked the plug wires. One of them was laying on my headers, it was burnt, changed them, it was a little better but still had problems. To keep it short, due to a surplus of cash at the time, I bought a new carb, help a lot but still had issues. Got pissed and decided to throw parts at it. I ended up changing the vacuum lines, fuel pump, and plugs. The plugs I pulled out were not that bad, but were put in before an HEI was installed. They were gaped at .35 so with the new ones I changed it to .45, also, the plugs for number 5 and 7 cylinders were very loose, I could turn them by hand. Anyways, after all this the truck was running tits.

I would suggest changing your vacuum lines, if you got a TH350, that one too. Change your plugs and wires. Rebuild or buy a new carb(if needed). And a fuel pump. Of course you will do all this after checking your timing. O yeah, change your fuel filter(s).

[suprachrgd82]

Newer fuels have increasingly higher ethanol content. Ethanol is has a tendency to degrade rubber fuel lines, allowing the fuel line particles to accumulate in "bottle necks" and fuel filters. It is quite possible that this a contributor to the condition.