Hi Norm,Tyler,Mf and speedy,

I would try a different spark plug and every mower I work on the carby is dismantled and cleaned then reassembled ,it
only takes as little as 30 days for fuel to go stale ,chemicals in the fuel can varnish up the inside of the carby blocking
important passageways inside the carburetor.

https://www.briggsandstratton.com/n...roubleshoot-your-mower-not-starting.html

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Cheers
Max.