Try installing a NEW air filter.

Are there any other symptoms? Drinking gas, burning oil or exhaust smoke? Did the old plug foul out?

Thank you for the replies and yes the old plug was fouling out and there is a lot of black exhaust smoke when I start it.
Alan

As stated above, a new air filter rather than cleaning. It isn't meant to be serviced. Tamped out at best. The good news is, the common Briggs 491588 filter is the same if no Honda filter is on the shelf. When checking your oil level, just rest the stick on the top of the tube. The oil should be in the cross hatched area. If it is overfull, the level needs to be reset and also confirmed that it doesn't contain fuel (like from the carb overflowing into the engine.) Black smoke on these isn't uncommon on start up, but should quickly go away as the choke opens.

Thank you tomplum I'll try A new air cleaner and recheck my oil level

Alan

It's running rich. Look first for a choke problem. it could be the throttle/choke linkage if so equipped. If the choke is opening properly, the next possiblility is a stuck float in the fuel bowl. Pick up the side of the mower with the carburetor and drop it a few times from about six inches. Then get a clean catch can, open the fuel valve, locate the carb drain screw on the lower front side of the fuel bowl and drain about a cup of fuel through. Turn off the gas valve and replace the screw. See if any particulate matter is in the drained fuel. Open the gas valve and run the mower to see if there's any improvement. If not, while the mower is running turn off the gas valve and see if running improves as it leans out. That would again point to the carb float/inlet valve.