hard to start Toro 22" mower

I have a one year old rear wheel drive Toro recycler mower with a Quantum B&S 190cc engine. It is hard to start. I can start it by tipping it on its side for say 20 seconds and then pulling the cord. It then runs for 20 seconds and then quits. I repeat the procedure and then it starts and continues to run OK. I have checked the jets in the bottom of the carburetor bowl, changed the plug and filter and replaced the gas to no avail.
Has anyone seen anything like this before?
Derbyken

Well, sounds like...when you lean the mower on it's side the fuel gets to run over into the intake slowly, then it starts & runs until it's out of fuel and dies.
So, first...disconnect the fuel line to the carb. See if the fuel will flow out of the line freely....if it does then the tank outlet is not stopped up, so it's gotta be inside the carberator. Take the carb. OFF, this time disassemble it all the way & clean it well. Take a good look at the needle & seat, amke sure it's not sticking. Try that and post back.