318 2 barrel Stromberg Accelerator Pump Flooding - 1964 Dodge Polara

[Dickey]

I've noticed a peculiar behavior with the Polara's carburetor since I've had it and I'm curious if this is a known issue in Mopar circles. I tried searching but I didn't find exactly what I was hunting. My issue seems to be that my accelerator pump is leaking. It still works to squirt fuel on quick throttle events, but when the car sits and idles it runs insanely rich and with the engine off, and the electric fuel pump regulated down to 1psi gasoline seeps around the lower gaskets and the throttle shaft.

I had noticed this earlier with the original Stromberg to the engine that I rebuilt shortly after I got the car. The accel piston would bind so I reused the old one to get by. I chalked it up to me doing something incorrectly and purchased a rebuilt carburetor from an ebay seller who had 100% feedback on his rebuilt carburetors. As far as I can tell, opening the throttle lowers the accelerator pump linkage and allows an internal spring to push the piston down to squirt fuel into the carb throat. It appears also that this linkage also regulates how far down the piston is allowed to move during part throttle.

When I rebuilt my carburetor, the new piston would bind in the cylinder and the car had zero accelerator pump action. The replacement carburetor did this same thing. I gave it a hundred miles to clear up but it did not. I pulled the top plate off of the carburetor and lightly sanded the sides of the piston so that it would move easier within the bore. This worked great for the last 1000 miles or so but I noticed this evening that it is idling rich and seeping fuel again. I also pulled the breather and saw that the linkage no longer pulls the piston as far up as it use to. It is short about an 1/8th inch or so.

Is this some manner of common failure that is easily remedied or do I just have uncanny luck in what not to own for Stromberg WW carburetors?

 

[1948 santa]

Rebuilt my Stromberg with kit from NAPA with no problems.

 

[383man]

I rebuilt a few back in the 70's. But check the throttle shafts for to much play (wear). If they are to sloppy then you either have to have them bushed or replace the carb. Myself on one that old I would replace the carb if the shafts are sloppy. Ron

 

[Dickey]

I did purchase another carburetor over dealing with the original. The throttle plates looked fine when I got it but I did not actually check the clearances. Were they leaking air, that would cause an erradic idle and lean out the the fuel mixtures at idle?

This week I pulled the top plate off and rechecked the float. It was 7/32's at the end but apparently it was supposed to be in the middle where it gets checked as I found on some threads across the interwebs. I adjusted that and put it back together. I no longer have my fuel seeping issue around the base at idle from too much enrichment. I'm going to reset the idle screws with a vacuum gauge this afternoon after I get back from running errands.

Of course, since I touched it last now don't have a good accelerator pump action. If I press the throttle directly it bogs. If it tap the throttle and then press it runs just fine. Seems to only be an issue off idle and under load. I cannot duplicate the behavior standing next to the car and looking at everything while I twist the throttle.

As an aside; I have three accelerator pump linkage positions on the throttle bracket. Adjusting from lower to upper, these allow the accelerator piston sit lower in its bore. What is the purpose of this adjustment? It seems to me that simply shimming the piston shaft relative to the linkage would have allowed greater resolution in where the piston sat relative to the throttle position.