Hi,
I have a Farm and Fleet garden tractor with a Briggs 20 HP V Twin engine. It started running lean recently. If you run at 3/4 choke, it runs OK. But will not run past idle when warm and the choke opened.
I noticed the fuel filter bowl seemed almost empty. I replaced the pump thinking it had to be at fault. No luck with that!

Can valve miss-adjustment cause this? What is the likely reason this engine is starving for fuel? Thanks for any ideas!
Dan

Remove the carb and clean, reassemble, and adjust.

If the fuel filter bowl is almost empty you may have debris in the tank. Disconnect the fuel line just at the filter inlet. Allow some fuel to drain to see if the line is clear.