I have a 351 Modified that will start up but not stay running, It seems like a fuel delivery issue but I am not sure. I've not worked on a motor older than 1987.

Does it run okay after it warms up? If so, it could be the choke pulldown adjustment?

See that's the thing, I can't get it to stay running long enough to warm up. It acts like it's not getting enough fuel. Are these motors supposed to have fuel pressure regulators? I'm not sure. I'm new to the Ford scene. I'm used to working on Mopars.


Sent from my iPhone using Tapatalk

There is no pressure regulator. You are limited to whatever the fuel pump produces, which is typically 5 psi +/-. What is the condition of fuel pump, fuel filter, etc.?

If it warms up just fine, I'd doubt it's the fuel pump, but pull the line off at the carb, turn the truck over and see what kinda flow you're getting. Otherwise I'd start thinking vacuum, choke or floats.

The fuel pump is in good condition. It's actually daily new. Previous owner put an in line clear fuel filter between pump and carb.


Sent from my iPhone using Tapatalk

I'm also having an issue since this motor came from a 79 F-250 and was put into a 86 F-150. I have it able to run as long as I have my foot on gas. But it doesn't idle under its own power and I don't have any alternator wires for the motor. I had someone suggest using a one Wire alternator but I have no clue how to go about that or what one to get.


Sent from my iPhone using Tapatalk

Does it still have an EGR valve? Might be a possibility, if the EGR valve is stuck open?

I can only speak from experiences I have had.

It does not. The Carb on it is an aftermarket 4 barrel.

I'm having a similar issue but it's intermittent. In the past I've had both a fuel pump and distributor issue. I'm working from the tank up.

I have a aftermarket fuel filter on the line between carb and pump. the previous owner put it on. I'm wondering if that might be causing the issue.

That shouldn't cause a problem

I don't know what else might be causing the issue then. unless the fuel pump is malfunctioning. but the inline filter is filling up like You would expect with the fuel pump functioning properly.

Sounds like the carb needs adjusted correctly.

Do a fuel pump quanitity test to make sure that the pump is working correctly.

Along the lines of what Ben said, is the timing ok?

What model of carb is it?...it might be worth going to that manufacturers site to see if there is a base setting.

its a holley 4 barrel with a tag from MotorCraft but i'm not seeing anything else to identify. I've been thinking of an EdelBrock for it. Its got so many issues in it already. its a 79 351m bored out to 400. that was placed into an 86 F150.

Float level is not set properly. set the floats.
You also have a vacuum leak, carb is probably loose.

As far as the alternator, I would suggest a 3g out of a ford Taurus

You can get everything you need off a car in the junk yard.

sounds like you have a holly 4180 which would have been a factory ford carb and are a bit different then and aftermarket holly 4150 or 4160.
how much do have to open the throttle plate to keep the engine running? did you re build the carb or had is been sitting?

if the floats are set right, and you have good fuel pressure, no noticable vacum leaks (unplug and cab all holes on the carb just to be safe)
https://www.youtube.com/watch?v=ge-mIk6nEYQ

the idle fuel circuit may have an issue and opening of the throttle plate will open up the transition circuit to get fuel. adjust idle mix and see if this helps and or tear down the carb and clean.

good reads
http://www.bob2000.com/carb.htm

I really have no idea about anything on this truck. I bought it off a friend who was got it the same day he sold it to me. I'm pretty sure the motor sat and I'm also sure that nothing was changed on it once it was put in the 86 body. Its a whole mess of headaches but once I get into it, Itll still be a great truck.