This problem is a frequent occurrence on the Solex Marine 44PA1 carburetor, but it can easily be fixed and you won’t have to buy another carburetor.
This can be caused from years of over tightening of the accelerator pump cover resulting in a warped cover. Whenever we rebuild one of these carburetors we resurface both the bowl and the accelerator pump cover. We have a nice flat grinder that does a good job, but you could also use a good flat file. Make sure you keep the flat file flat on the surface and file from all angles. The high spots will be at the screw holes. You could also use a little Permatex Anerobic gasket maker, but use very little and only around the outside edge. You don’t want any mixing with the fuel.
YF Metering Rod Adjustment
The adjustment below is for early Carter YF carburetors that don’t have an adjusting screw at the top of the metering rod. Most YFA carburetors would have the star type of adjusting screw.
This adjustment is important and should be performed anytime the carburetor is rebuilt, or the metering rod replaced. With the throttle valve seated (this means the idle screw is not holding the valve open) in the bore of carburetor, press down on upper end of diaphragm shaft (C) until diaphragm bottoms in vacuum chamber. On carburetors which have the projection (D) on the pump lifter link, metering rod should contact the bottom of the metering rod well (E), and metering rod arm (F) should contact lifter link (G) between springs and at supporting lug (D). Adjust by bending lip (H) up or down. In the illustration there is a tool that can be used to hold down the diaphragm, but chances are you won’t have one of those and it isn’t that big of a deal to hold it down.
On models that do not have the projection (D) on pump lifter link, the metering rod should bottom in the metering rod well (E) and flat of metering rod arm (F) should make parallel contact with flat of pump lifter link (G). Adjust by bending the lip (H) up or down.
Adjusting the Accelerator Pump Stroke for Seasonal or Climatic Changes. Holley 1904 The accelerating pump stroke can be adjusted for seasonal or climatic changes by changing the position of the pump link in the throttle lever. The hole in the lever nearest the throttle shaft is the normal setting and should be satisfactory for nearly all operating conditions. If a richer accelerating pump discharge is desired for extreme cold weather operation, set the pump link in the outer hole in the throttle lever. Pump link position can be changed by removing the cotter pin at the lower end of the pump link, moving the pump link to the other hole, and re-installing the cotter pin.