Opinions On Pooped PumpsIn the January issue of SRM, we ran a letter from Hank Young concerning a carburetion problem on his '35 Ford. His complaint concerned a sticking accelerator pump. Not the first letter we've received on the subject, this issue has come about because the additives used in some of today's blended fuels cause the accelerator pump cups to swell and stick. Coincidently, we had been speaking to one of the best carburetor guys in the business, Henry Olsen (Ole's Carburetor & Electric, (650) 589-7377), about that very issue and showed the parts he uses to solve the problem.
Just recently, we received an e-mail on the subject from another carburetor expert, our old friend Larry Fulton (Automotion, (406) 453-5395). Here's what he had to say.
I've got to give you my two cents here on your photo caption on page 206 of the January '07 STREET RODDER, which states, "The style on the left may cause problems in 2G Rochester carburetors." I have been using this garter spring-style pump for many years now with absolutely no troubles!
Our experience has shown that the garter spring design is the way to go, because this spring actually exerts a small amount of pressure from the underside of the cup lip. This keeps the lip planted against the wall of the accelerator pump-well during the pump stroke, which gives us a stronger, more consistent pump shot. If you like the "thin lip" design, so be it, but don't say the "pump on the left doesn't work."
The write-in question was about the pumps sticking. Here's the skinny on that. The biggest factor in pump effectiveness is in the cup material. Most all or any of the black cups are Buna rubber and this material has a tendency to deteriorate, swell, and/or stick the pump-well when used with today's fuel blends. I have always used a premium blue pump cup that is constructed out of a fluroelastomer material to be ethanol-methanol resistant, and while not perfect, these still hold up much better than anything else out there that we have found. In my opinion, it's the cup material that matters the most.Larry Fulton Via the Internet
Larry Fulton and Henry Olsen are two of the sharpest guys we know on carburetion. While that doesn't mean they agree on everything, it does mean they may address the same problem differently. Clearly, each of these guys has a combination of parts in which they believe, and more importantly, stand behind.
That being said, we need to clarify our stance. We didn't say, "The pump on the left doesn't work"; we said there might be problems with that style-a statement we stand behind. We have had issues with the style of pump shown swelling up and sticking. However, it should also be noted that they were not the same pumps Larry uses.
The pumps Henry prefers to use in 2G two-barrels are made for Quadrajets, Varijets, Dualjets, and Monojets to combat the issues that make the pumps stick. (Henry adds that the manufacturer did not address the 2G or 4G carbs because they didn't sell enough kits to make it worthwhile.) It should be noted that these pumps have differences beyond the elimination of the spring that include the material, shape of the cup, and thickness of the lip.