Engine Runs slow for 1 or 2 minutes when first started.

The subject is a Cub Cadet SC 100 push mower
model: 11A-A92J710
serial number: 10163K11439
engine: 159 cc OHV serial number: 5X65RU/1211151A0162

Engine ran fine the first couple of times this year. Now, when started, it runs slow for a minute or two, and then transitions to operating speed. Fresh gas. Fresh oil. Clean air filter. New gas filter. Plug cleaned and gapped.

Any ideas?

https://www.cubcadet.com/equipment/...elNumber=11A-A92J710&serialNumber=10163K11439

replace spark plug, let us know how it goes.

https://www.amazon.com/MTD-951-10358A-Replacement-Part-Filter/dp/B00Y0OG79U?tag=viglink22747-20

https://www.google.com/search?q=cub...ome..69i57.35408j0j4&sourceid=chrome&ie=UTF-8