Rochester Products produced many different varieties of accelerator pumps for the Quadrajet carburetor. Most differences were due to minor changes in pump plunger stem lengths and compression spring heights. Three different styles of pump cups were used, but all Rochester Quadrajet carburetors use a 21/32" pump cup OD. The 3 styles are the long skirt cup, the double lip cup and the garter spring cup. All 3 styles were originally effective in producing a solid accelerator pump shot of fuel, but not anymore. Any style can be used in any Quadrajet but the individual components of each of the 3 pump styles are different and may not be interchangeable. Each style uses a different plunger assembly and pump cup.
Three styles of Rochester Quadrajet Accelerator Pumps are shown both with and without the pump cups installed.
|Garter Spring Pump||Double Lip Pump||Long Skirt Pump|
Garter Spring Accelerator Pumps-
We feel that this is the best pump for the Rochester Quadrajet. This pump incorporates a circular garter spring within the pump cup to apply positive outward pressure and prevents the possibility of the cup deflecting inward. Our #1003 & #1004 accelerator pump assemblies are garter spring style pumps that has been redesigned to accomodate todays alcohol/ethanol enhanced fuels. Its body has a metal cap that positivly retains the plunger shaft to the body and incorporates a garter spring style pump cup designed to resist the ethanol enhanced fuels. Garter spring pump cups are available seperatly part # 1010.
Double Lip Accelerator Pumps-
This style pump was used by Rochester Products on some Quadrajet models. If your model carburetor has this style accelerator pump you have 2 options, you can retain the original pump assembly and update it with a new ethanol/alcohol resistant double lip pump cup (#1012) or you can replace it with our #1003 or #1004 pump assembly. We have discovered that some of the blue ethanol rated double lip accelerator pump cups on the market are too soft and end up falling off plunger during operation. We use a stronger/stiffer double lib cup to preventy this issue.
Long Skirt Accelerator Pumps-
The long skirt (#1013) design features a pump cup that is taller and slightly wider than the garter spring cup. This style pump was used by Rochester Products on many earlier Quadrajet models.
NOTE: We do not sell the #1013 (Long Skirt Pump Cup) as it has a tendency to roll over on itself and either binding up the pump assembly or disconnecting from the pump plunger assembly.
If your model carburetor has this style accelerator pump you have 2 options, The best option is to replace it with our #1003 or #1004 pump assembly or you can retain the original pump assembly and update it with a new ethanol/alcohol garter spring pump cup (#1010). The #1010, used without the garter spring on Long Skirt style pump plungers has performed well in our testing.
Long Skirt Pump Cup
The Ethanol Problem
Today it is very common for the fuel at your local gas station to be a mixture of gasoline and ethanol.
E-10 10% Ethanol
E-15 15% Ethanol
E-85 85% Ethanol
The ethanol (even at only 10%) has disastrous effects on older carbureted vehicles. The ethanol attacks the rubber in the fuel system. (Accelerator pumps, rubber fuel lines) The older black accelerator pump cups worked fine with straight gasoline, but the 10+% ethanol really wreaks havoc. The ethanol causes the rubber cups to swell substantially in a very short time (several days) causes the pump cup to roll over itself and disconnect from plunger assembly, usually ending up at the bottom of the pump well causing the accelerator pump not to function at all. Our pumps and pump cups are all rated for use with ethanol. Note: Do not allow carburetor cleaner to come in contact with accelerator pump assembly.
Problems with Accelerator Pumps in "other" Rebuild Kits
Carburetor rebuild kits sold by "other" vendors and chain auto part stores may or may not contain non-compatible pump cups (there are thousands of kits sitting on warehouse shelves. In today’s world, vehicles with carburetors are a very small minority, and they are not going to go thru every kit to update it with correct parts) Some of the "other" kits may contain blue colored pump cups, but they are about as effective as the old black/brown cups, usually falling off the plunger in a few days of use. All of our accelerator pumps and rebuild kits are ethanol compatible and the pump cups won’t fold over themselves. We don't sell parts that we know don't work.