The very first thing that you will want to do is to check and see if gas is in the carburetor bowl. If the bowl is empty, you will then proceed to check if the valve is stuck. A stuck carburetor valve is a relatively common problem and is most associated with gunk build up. A Briggs carb issue is one of the most common issues lawn mower owners are faced with especially in the hotter months of late summer.
Flip Mower Upside Down
If there is no valve problem and you have determined that there is no obstruction in the bowl itself, then it is time to move onto the underside of the mower engine. The best way to do this is to turn the mower upside down. Once you have the mower in the upside down position, you may then take a quick look at the float. A stuck float is much like a stuck valve and will be the second leading cause of a carburetor problem. The float needs to be checked regularly, as in the summer months, it is easy for these floats to become stuck and gunked up with debris and gas sediment.
How to Maintain a Briggs Carb on Lawn Mower – Valve and Float Sticking Issues