I have a 1961 292 in one of my '54 Fords with the original factory type double action AC fuel pump.  I now have a massive fuel leak.  Every time the pump activates, a large stream of fuel squirts out of one of the vent? holes located just above where the fuel line connects to the pump.  I have never had that happen before.  What does that show is wrong with the pump?  Also, I will probably need a replacement and I want to stick with the AC factory type.  AC pump #'s 4206 and 4486 look almost identical but one is for Ford and one supposed to be for Mercury.  What is the difference and will either pump work on my 1961 292?   Which is the correct AC pump number for this engine?  Thanks

I am going to guess here.  Most likely, the difference is in the location of the inlet and outlet.  I have seen a number of these pumps and that seems to be the difference.  What I don't know is if the psi ratings and flow ratings  are different.  On some, the lower bowl is smaller than  others.  These are pumps w/o the bottom filter but it may be the same deal with the bottom filter..

As an example, I was looking for an extra pump for my TBird.  A guy was advertising one for a Tbird.  It looked kosher so I bought it.  Turned out, the pump was actually for  a 60  Edsel, some later Fords and Mercs.  The inlet and outlet were reversed.  I could not use it because I was running the stock set up and the hard lines would not line up. I still have the pump even though I have tried to sell it.

Best bet is to have yours rebuilt.  The new ones today are pretty much junk out of the box.

Sounds like the diaphragm gave up the ghost.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ