4 years now trying to start mower

Hello. I have had yard service for the last 4 years, but now and needing to do myself. I have a 7 year old Toro Recycler with a B&S 6.5 (190cc) engine. In prepping it, I siphoned out all the old gas, got new gas, and replace the spark plug and air filter. After 40+ pulls, I still have a no start condition (its not even trying to turn over).
Thoughts? Could the fuel filter have gone bad> I ask as I pulled the air filter off again and when priming, and caught no sense it was truly priming.

Just because you drained the tank doesn't get the crappy gas out of the carb. I got a new mower in yesterday that was purchased in November of last year that the customer said has never started. Evident by no grass under deck or on blade. Checked fuel in tank and found to be good, removed the carb bowl and found what looks like skim milk. Drained carb, and then put the bowl back on and started the mower.