Technical 1953 Mercury dual action fuel pump problem

I have a 1953 Mercury with original flathead engine. I am having trouble with the fuel pump. I have tried three different fuel pumps and the same thing happens:
After installing the fuel pump (and filling the fuel pump filter bowl), I hit the starter button and only one spurt of fuel comes out, then nothing. I take the top portion of fuel pump off, only to find the diaphragm rod is not connected to the cam lever assembly. The vacuum portion is still connected.
When installing the fuel pump, I leave the existing pump push rod cover on, then manipulate the pump into place.
Is there something I am not doing correctly, or what would cause this to happen?
Thanks

 

Think I will pose this question to people who rebuild fuel pumps, such as then and now, etc.
In the meantime, I will look over one of the spares I have to see if I can diagnose why the problem exists.

 

Just a thought? I have seen the rod that operates the pump some times becomes short due to wear. My $0.02

 

Dangerous Dan is right! We used to build up pump rod by welding pump end, filing and polishing and replacing. It was quite common practice. Today, you just buy a new one.

 

Guys, the pump rod wear is certainly possible, but 3 pumps having the same issue? But I will check my spares to see what the "hook" end looks like. I am thinking that the round end of the rod (takes in the camshaft push rod) might have something to do with the problem.

 

Let us know...........

 

@Lost in the Fifties nailed it. If all 3 pumps won't work, it's definatly the fuel pump rod has worn out (too short)...a very common problem on Flatheads. As mentioned, a spot of weld on the end of the rod will add length to it...an old time trick.

 

What end did you weld and how much did you add to it

 

Add to the pump end. Add enough weld to be able to file it down to a 10-1/16 (10.0625) finish length...OR save yourself a lot of work...
1949 - 1953 Ford Flathead V8 Fuel Pump Rod | eBay

 

Thank you

 

May also be the fuel pump cam lobe went flat on you. I have heard the "Dual-Action" fuel pumps (as used on Mercury's) can have that effect.

 

Also, some aftermarket aluminum intakes are slightly thicker than original cast iron and that cam make the rod seem too short. Even a thicker intake gasket can affect it too