It sounds like this happened suddenly. Check your bowl nut (jet) first.

Shown are 3 of the typical jets and the small holes. All 3 are Tecumseh jets. Briggs jets are similar with the center-bottom hole and one on the side. All these holes need to be fully clean and open for the engine to run correctly.
Some jets only have the center-bottom hole.

{{gwi:126850}}

{{gwi:126851}}

{{gwi:126852}}

Great photos and suggestions. I flatter myself that I am good at rebuilding the IH carburetors on Farmall Cubs. Those jets have some similarities to the Cub but not the easy accessibility of the IH carburetor jet.

For any who are interested, the jet is the bolt that holds the bowl to the carburetor. a 1/4 drive ratchet with 1/2" socket worked best for my case. Just unscrew the bolt from the bottom. The gasoline in the tank will run out! Don't do this inside the garage. In my case, I let the bolt/jet dry thoroughly and placed it on clean white paper while cleaning. Used a hand sewing needle to clean the hole. Surprised at the debris that fell out. Just reinstalled the bolt/jet and it has run perfectly ever since.

The most versatile tool you can buy for jets is a tip cleaner set for gas welders. The uniform diameter of the wire is perfect for jets.

But, only use the smooth part of the tip cleaner wire. DO NOT REAM WITH THE ROUGH PART!
Also, either drain out the gas tank, or clamp the hose with Vise-grips. You do own a pair of Genuine Vise-grips, don't you? A handy tool for lots of things, especially for keeping gasoline in the tank, not on the floor!

Yeah but go gently on the vice grip pressure mate !

I always use two steel washers, one on each side of the hose, with light pressure on the grips.