how much time passed between the last time it ran well and this time?
carbs will varnish up quickly, even quicker if fuel stabilizer isnt used,
I have a few customers that dont get it so I have done the carbs every spring for almost 20 years

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test spark, test compression and go fix the fuel system, I really doubt you will see a pump issue as when you prime it, it simply bypasses the pump and fills the carbs.