How long to run a near full gas tank out? Push mower?

Is a Honda gvc 160 4.4hp. I would drain it from the gas line but I've got some Lucas injector cleaner in it.So about how long do y'all think? And yes I've already cut my yard two days ago.

A push mower fuel tank is usually a pint or less, which is usually good for 2-3 hours service, without refilling. Within 4-5 hours it should be completely dry and shut off. A piece of string will usually hold the shutoff switch in lace to keep it from shutting off while it runs "unattended". Remember, it is not safe to leave the area, while it is running - keep it within visual and audible range - while you too, are out doors, nearby, doing something productive.

What do you think the tank capacity is?