The carb on my latest purchase will not pump gas through the jets and will not start without being primed after sitting overnight. I assume the accelerator pump is not working but not sure. If it is the pump what should I look for as the likely cause and are they easy to fix?

It all depends on your mechanical abilities. If you have a decent mechanical aptitude there is nothing difficult about changing any aspect of an AFB, pretty basic carburetor.

A total lack of fuel is not usually an accelerator pump issue, it's likely a float or needle and seat issue, or something outside the carb restricting fuel.

Overnight fuel dissipation is common with todays fuel, most likely it's just evaporating, an electric fuel pump will compensate for that.

thru the AP nozzle (squirters) I am assuming you are meanin. (1) when you shut it down for the night before you go inside, pull the air cleaner & pull the throttle under the hood & see if you have immediate tip in & a healthy stream duration/amount (2) the next AM before you crank it, same thing, see what you have for a stream. If (1) is good & (2) ain't then its evaporating from too much heat soak. If (1) ain't right then pull the rods/carb top & see what is up with the pump plunger assy. it should grab ~halfway down the bore. there just was a thread where the check valve for the pump well was not doing its job. dont remember if the well was not filling or if the check ball was not letting the fuel being pushed out to the squirter but it was the check valve. EDIT & there is a check valve (ball bearing or long needle valve) under the squirter also

Took the top off the carb and the accelerator pump is the leather type. Tried to use it manually with fuel in the bowl and with the squirters off and got no fuel up to the squirters' holes. Even tried blowing air through the passage and got nothing. Should I be able to pass something from the base, through the passage and up to the squirters? The carb runs nice all except for not getting any fuel to the squirters right now.

[quote] Should I be able to pass something from the base, through the passage and up to the squirters? [quote/] yes, its plugged

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

I have found the squirters on the old AFB's to be WAY too small in general. I usually open them up to at least .030 or more.

The check valve is free. Now that the gunk is out of the way it is easy to see what is going on. Soaked the leather in WD40 and mannually gave it a few pumps and the squirters are doing their thing. Hopefully get time before the end of the week to re-install the carb and prove the fix. Thanks for everyone's help.

Does yours have a check valve on the outside of pump plunger area? They will stick on occasion also leave the accel pump sit in clean motor oil it may swell up if its leather

maybe I missed it but was the passage blocked or was it the check valve under the squirter that was stuck? on a leather plunger what Cab said run a screwdriver inbetween the spring and the leather around it to expand it & I would oil the leather to make it supple/fit better

The check valve was stuck. Once it was free all was good. I did take cab's advice and massaged the spring and leather. I also soaked it in WD40. Re-installed the carb, turned the 413 over several times to fill the bowls, confirmed the squirters to be doing their thing and fired it up. No rebuild kit yet. It seems to be running fine. 😎🙏

The valve was up top under the squirter body.