I have a '76 f100 sb 4x4. The problem i am having is the fella i got the truck from jerry rigged evrything on the engine. the dist. vac advnce isn't hooked up. choke was converted to a manual. but choke doesnt open runs real rich. has a electric fuel pump. some days it runs good other days it will run but at 200 rpms with ur foot to the floor. please any and all help is greatly needed.

 

I'd start by connecting your vacuum advance and fixing your choke then see where things stand after that...

 

I second Montana, Fix the obvious then go from there. Hook up the vacuum advance, check and make sure the advance unit is good, then fix the choke. Sounds like it's running way too rich. With an electric fuel pump you might have to add a pressure regulator.

 

ok hooked the advance up truck dies so im replacing it. as for the choke if you open the choke the truck dies. so now what?

 

Sounds like it may be out of time, get it running and check. you may need to do a good tune up if it was jerry rigged more than likely it wasnt done either. Like mike said with a electric fuel pump you may need a fuel regulator, and carb may need to be rebuilt.

 

If it runs with the choke closed but dies when the choke is open means it's probably time for a carb. rebuild, but first try adjusting the idle mixture screws (if possible).

 

If the engine runs with the choke closed but dies when the choke is opened, you're not getting enough fuel into the engine, possibly due to dirt in carb plugging the jets, plugged fuel filter, inadeqate fuel pump pressure. The reason your engine runs only with the choke closed is that it is compensating for lack of fuel by closing off the supply of air. I'd first check to see if you are getting enough fuel to the carb. If that checks out OK then it's probably time to clean and rebuild the carb.

 

put a new dist.in hooked the advance up. idled really good but went to drive and the truck hesitates sputters but push the clutch in and idles smooth. put it in reverse and drives fine.the carb i believe is a lost cause,prolly just get a new one. there is a lot of stuff thats missing not hooked up.butif the timings set right other than the carb what else could it be? and should i change over to a 4bbl instead of the 2 bbl?

 

I'd keep the 2 bbl. An electric pump should be mounted close to the tank. Electrics are pusher pumps whereas mechanical pumps suck the fuel.
I'd also check all the hoses in the fuel system. If they are old and cracked replace them.
You might still have to install a pressure regulator if you keep the electric.

 

Sounds like a fuel issue to me too. However, I would hook up a timing light, vacuum guage, and tach and see what you got going on, this will tell you a lot of what is happening. Also by the sounds of the PO, I would put new plugs, wires, cap, rotor on it too. Then after you get all that cleared up and running right, I'd change the oil, then you know everything is new clean and fresh.

PS: What size motor are you working on, and how many miles are on it?

PS II: Did you look at the fuel filter??

 

tees77f150- fuel filter was replaced, engine has 14,000 miles since it was rebuilt, engine is a 360 supposedly uped to a 390. but i dunno for sure.i got the regulator just need to put it on and also an inline fuel press. gauge.

 

replaced old dist with new one, put the gauge on the fuel line showing bbout 3-4 psi at the carb. now i think the carb is the problem. since half the mess on the card is mia or broke prolly be best if i just replaced the darn thing.

 

If it runs better with the choke closed it can also be a vacumn leak.
3 or 4 pounds fuel pressure seems low what does it call for.

 

Your fuel pressure is low.
Spec is 5-7 psi.

 

Start at the tank, drain it and flush, run a new fuel line to a new manual pump( put the electric one in the tool kit for fuel transfers and emergencies), Get the carb to the oldest alcholic mechanic in town who probably has seen and rebuilt 43,000 of them in his career. Tell him to see what he thinks, but not to fix it without an estimate. When you get the carb back with new kit in it, and new gasket. Change the vacuum lines, chk the timing, and tryer!