Clean, new gas (unleaded) but gas drained and refilled & topped with "engine mechanic" fluid just in case.
New spark plug.
Needs new filter but existing one removed and brushed out.
Ran a month ago w/o problems. Cranked on first pull. Never had a starting problem before. Always cranked on first pull.
Mower hardly used. Stored in dry shed when not in use.
All mower repair folks around here are backed up for weeks or do not respond. One shop charges $115/hour!