I have a 75 F700 fire pumper with a 390. Just put in new points etc. Didn't want to pull a load or rev up. Loosened up a line from the carb to base of distributer, and it runs great. Tighten the line up- runs pooly again. I. no Ford guy, gut whats up????

 

What line are you talking about? The only thing that goes from carb to distributor is vac advance.

And you may be better off posting in the 73-79 forum. This is 67-72.

 

Welcome to FTE

I asked a moderator to move your thread to the LARGE TRUCK forum, this forum is for 1967/72. With an F700, you won't get much help in the 1973/79 forum which is mostly related to F100/350's.

Your truck does not have a 390 FE engine, as these were only installed in 1968/76 F100/350's and misc 1961/71 Passenger Cars.

More than likely it has a 391 4V FT engine.

 

What happens when it won't rev or take a load? Does it miss, or just not rev?

That line might be the governor.

 

It just won't rev. It will when the line is loosened up. Wold the gov be vacuum operated? I'm not a Ford or truck guy

 

Distributors and carbs in those trucks usually had a governor on them. If the gov were disturbed in some way, that might be an issue.

Usually we get the report that the engine will rev with no load, but no revs or power with a load. That is many times a fuel issue.

Since you were in the distributor, my guess is a governor issue.

The line from the carb to the distributor--loosening it up--what do you mean, did you disconnect it, unscrew it partially, what? Usually a line is either connected or disconnected.

 

yes the line was disconnected and it ran well

 

Yes the gov. is vac operated and you dont have to be a Ford guy most
all work the same. What you say (and sounds like) the diaphram part on
the carb seems to be working, when the line is loose, sounds like the
pendulum in the distributor is stuck or the spring is broken? Although
a tough job while in the truck, its best to pull the dist out. There is two
lines there one from the gov to the diaphram Pass side (carb) and one
is the vent that goes (driver side) into the carb air horn for clean air.
To set these remove the clean air hose remove its barb on the dist. its
a square (barb) which is access to the gov. the bitch part is to turn
engine by fan or bump it till the pendulum comes around to the hole where
a allen set screw shows with allen wrench clockwise increase speed and
counter clockwise decreases speed against spring tention. Sounds to me
the pendulum is stuck out (centrifical gravity) which closes the clean air
line inturn gives vac. to the diaphram thus the engine wont speed up.
First test is take off the line at the diaphram while running put your finger
on the fitting there should be vac==race engine up then put finger back
on and the engine should idle no matter where the throttle is. If good the
problem is distrubutor. hope I my writing is understandable best I can say.
My bets are its a 391 with 2 or 4 bbl square bowl Holley notorious for
loading just about running- black smoking- when its rain & snow around 38 to 40 degrees they get carb icing. we run them for a minute shut down and
walk a way for a bit then restart they just need a little engine heat.
sam

 

Would there be any problems with leaving the line disconnected?

 

No but I recomend some kind of air filter perhaps a small pill container with
some foam so it dont suck up something or them mud wasps get in there..
sam