I recently purchased a 1972 Land cruiser with the original F engine. The engine idles rough and backfires and stumbles unless I set the timing way advanced ~30btdc. Everything appears stock. I’ve gone through the timing/dwell, full tune up. The motor has compression 130-150 on all cylinders. I believe my issues are related to the carburetor. I just rebuilt it with no change apparent. I noticed during the rebuild that I am missing the “pump discharge weight”. Someone had put two small balls instead of one weight and one ball. #22 in the diagram. I also have about 3/4 full in the sight glass. Would either of these things cause my issues?