I have a couple of spares if you want to try, I would say shipping would be less than 10 bucks. you could rule out the pump rebuild and know if it is working correctly.
Also I have a pump around system. If I let someone else drive the kart and it stalls I have to change the plug due to them lugging the kart around at lower RPM’s and then if they spin they tend to floor it with out pulling the clutch in. I can usually tell if it is flooded because when you push start it the engine sounds just like you have the throttle wide open while pushing. BAAAAA deep sounding.
I found that out the hard way, I adjusted the throttle to much “open” and about never got the kart started again.