How to fix a sticky Stromberg 48 accelerator pump?

[COE Dan]

Ford Barners,

I have a Stromberg 48 from a '34 Ford - everything is stock. The was rebuilt about 5 years ago with all new parts. I pulled the carb because the accelerator pump was sticking in the carb body and not adding fuel as designed. I've cleaned everything, replaced all the gaskets, and installed a new accelerator pump.

I haven't reinstalled the carb yet because the accelerator pump still sticks in the body. I disassembled everything again and found that the carb casting is mildly etched between the neutral (resting) position of the pump and the power valve. I'm assuming modern gas additives or other cause over time resulted in a rough inner wall. The resulting lack of smoothness causes the pump to stick in the depressed position. On the bench, this sticking occurs when the carb is dry (no gas).

Questions:
1) Will this problem solve itself when the accelerator pump is wet with gas?
2) If not, how do I clean up the carb body to allow smooth accelerator pump operation?

I'm concerned that I am too aggressive in my polishing effort will likely result a poor pump seal.

Any recommendations?

Thanks, Dan

[hardtimes]

Hey Dan,
You do not say, but is the pump leather type of new neoprene/rubber type ?
Not knowing which, I'd say ..if leather..given what you've told..I'd soak the leather pump with light oil (machine oil?). I have always done so and have never had a sealing/sticking problem.
If pump is of newer material, well I'd carefully clean up the pump well wall with VERY light abrasive and pressure, checking often for results. It should not take much to clean up a rough pump well surface, because it is soft 'pot metal' type material.
Also, 'uncle max' and/or other carb rebuild pros, may have some other better process for clean up the pump well. Good luck

[COE Dan]

The pump is the traditional leather type. I'll try the oil soak method first and see if that cures the sticking. If not, I'll move to abrasives. Thanks for the tip.

[uncle max]

Use a 5/8" diameter brass brush in your hand drill and run it in and out of the well a couple of times. The chamber will polish up nicely.

[COE Dan]

Ahh, that thought never crossed my mind...great idea! Thanks.

[hardtimes]

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Originally Posted by uncle max

Use a 5/8" diameter brass brush in your hand drill and run it in and out of the well a couple of times. The chamber will polish up nicely.

Hey Max,
Thanks for the brass brush (5/8") tip. I just knew that you would have figured that one out

[FlatheadTed]

I use a socket drive or hex bit extension ,wrap 400 grit paper around it interleaved with masking tap .wined ? the tap on then the paper follows .polish it up .some piston springs are weak ,I had to remove the small coil spring under the leather .Ted