Anyone out there with experience as an engine mechanic involving an older Ford 
390 engine, specifically the fuel pump? 

This is on a '72 F250 I'm gonna get ready to sell. Last week when it would not 
start, I disconnected the fuel line where it enters the carburetor and found 
that the (mechanical) fuel pump was not delivering gasoline to the carburetor. 
Knowing that the fuel pump has been in there since at least 1978 when I bought 
it, and possibly since new in 1972,  I was suspicious that it had failed. I 
bought a new (Carter) at Pep Boys and removed the old one (which involved 
disconnecting the power steering assembly and moving it aside). I then 
installed the new fuel pump and was disappointed to find that it did not move 
the fuel either. I then attached a fuel line to a container of gas and turned 
over the engine with the starter. The new fuel pump would not suck up the gas.

I then removed the new pump and tested it by running the fuel line into the 
container and moving the lever by hand. It sucked up the fuel readily.

Then I hooked up the old pump to the fuel line and tested it by hand. Lo and 
behold, it also sucked up the fuel just fine. This told me that my old pump was 
still working. I reinstalled the old pump and hooked it up to the container. It 
would not suck it up.

 

So, to review, both new and old (40 years old!) fuel pumps work fine when hand 
operated, and neither works when installed on the car. 

 

Enters now the possibility that I did not install the new pump correctly. 
However, if that is the case, why was the old pump not working before I removed 
it?

 

By process of elimination, I am left with the unhappy prospect that the lever 
on each pump is not being moved up and down by the cam lobe.  So I tried to 
peek inside that hole and noticed that there is what appears to be a chain 
inside, and it appears to be kinda loose, and I can move it by poking it with a 
screwdriver. When I crank the engine, the chain seems to move. I cannot see 
straight inside, but by putting in a screwdriver, I can feel what may be an 
eccentric cam, though I can't be sure. Looks like a huge job to remove the 
cover plate over this area to see what is going on. Hence my appeal to someone 
familiar with this area of this engine.

Could that eccentric cam not be moving? If so, if I run the engine, will I do 
more damage?

By the way, last time I ran the engine, it was just fine. Can't understand why, 
with the vehicle just sitting there, the cam would stop moving.

 

I plan to bypass the mechanical fuel pump and install an electric pump, but I 
worry that something is wrong inside the engine. What do you think?





Jerry

82 240D

72 Ford F250

and others



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