Lawnmower problems

Check the air filter. How old is the gas? If it is from last year don't use it.

No sure what type of engine you have, but if possible take the bowl off the carb( if it's a Briggs).Usually a 10mm wrench will fit, take the bolt all the way out and give the bowl a little twist and it should come off.Once off there is a needle valve held in place by a pin, slide the pin to one side and the valve will come out.Once you do that, use some air from a compressor or a can of carb cleaner and squirt in the valve seat, but not too much pressure, then put back together, Oh and empty the gas tank and replace with fresh fuel...Good Luck!

Sometimes taking the fuel bowl of is not required.
Sometime lightly tapping on the bowl with the handle of a screwdriver will dislodge whatever is stuck in there along with pouring a good amount of Seafoam into the gas to help brake up any other obstacles that may be hindering fuel flow.

If its a newer model mower than the carb will be sealed. Check the filter and fuel filter and hope for the best. A new carb is cheap though.

Your jet is stopped up or your float is stuck. Tear it down and clean it. You may have poured some trash in the tank from the bottom of your gas can.