reply to quatrix
Re: Lawn mower won't stay running Problem solved. I replaced the whole carburetor with a brand-new OEM part from eBay ($30) and emptied and cleaned the gas tank again. It started on the first pull, sounds good, and even handled the 10-inch-tall grass that had piled up while I was working on the mower. Thanks again to everyone who tried to help.
PacratOld and CrankyPremium,MVM
I love happy endings! Thanks for letting us know the final solution to the problem... too many do not.