Also known as the 4 Jet carburetor.

Rochester 4G, 4GC Carburetor Manual

Watch a video about the accelerator pump vent.

Watch a video about rebuilding the Rochester 4 Jet.

Watch a video about the Rochester 4GC integral choke.

Watch a video about the Rochester 4G jets.


Can one of the emulsion tubes be missing from the venturi?

Sometimes those fall out.  I would simply try to find another 4G and pirate an emulsion tube from its booster cluster.  Compare the size/number/placement of holes with the remaining tube and modify as necessary.  Install new tube to same depth as old one with a light coating of Permatex Anaerobic Gasket Maker on the press-fit surface.


When I took apart my 4gc (7024121) there was no aluminum check ball in the pump intake cavity. Does it take the large one or the small one that is in my kit?


1st you have to be sure you need a check ball. Carburetors that use a check ball in the accelerator pump well will have two holes at the bottom. One for intake and the other for out flow. When there is only one hole, then no check ball is needed since the hole is the out flow and if you placed a check ball there, the flow to the main discharge would be cut off. When you have two holes, then use the smaller of the check balls and these are often made of aluminum instead of stainless steel. Aluminum is used to make the check ball lighter since only the weight of the fuel lifts the check ball off of the hole to allow fuel to enter.