View Full Version : CJ-2 through CJ-6 fuel pumps and pressures

05-26-2021, 06:14 AM
This question comes up from time to time. These are the correct pumps and pressures for the early CJ's.

The service manual only lists three different pressures on the 134's with AC pumps. Though a lot of pumps could be on your 134, it was originally set up to run with one of these three. A lot of different pumps were installed. Use these pressures to keep from flooding. In the CJ2A the service manual is using the AC 153886. It should be internally regulated or use a spacer, at 4.5 psi max.. The CJ3A uses AC 1539353. It should be internally set or use a spacer, for 2 1/2 to 3 1/2 psi max. The rest through CJ6 use AC 5594032. It should be internally set or use a spacer, for 2 1/2 to 3 3/4 psi max. The WO Carter can take 4.5 psi if you have the right float, needle and seat in the carburetor that matches the pump pressure requirements. There are a few different float, needle and seat assemblies out there. If you are needing a regulator because the pump is putting out too much pressure and you have the right spacer, float, needle and seat, or you don't, you have two choices. Send the pump back or install a regulator in the line after the filter.

I have this pump from KW https://www.kaiserwillys.com/category/fuel/fuel-pumps-filters/new-fuel-pump-single-action-fits-41-71-jeep-willys-with-4-134-engine. It runs right at 4.5 psi. with no spacer, too much for an original 3A, but I have the early 2A float, needle valve and seat assembly.

The vacuum wiper pump should pull around 10 1/2 inches of mercury at 1800 rpm.