Pull the squirter nossle off and see if you can see the brass check valve under the nossle, if so try squirting a little WD 40 or Liquid Wrench on top of the check valve, let it sit for 5 to 10 minutes and see if it will come loose by filling the accelerator pump well and try squirting it with the accelerator pump manually If it is stuck in there, gummed up with varnish, you may need to take the carb. off the intake and get a squirt can of carb. cleaner and try and clean the gum and varnish out of that passage to free that check valve. Once the check valve is freed up and falls in and out of that passage easily it should work properly I use a thin blade scewdriver to move the leather out and around the spring to help it pump better also I have a AVS on a motor right now that has a poor stream of fuel, I didn't presoak the pump or try moving the leather skirt out I will in the morning before running that motor again on the dyno tomorrow