Startron costs a lot and is good for boats and I’d use it for that but for yard equipment I use marvel mystery oil. You’ll notice a difference. In equipment that has a carburetor it will prevent its passages from clogging, the needle from sticking , varnish buildup, seals/gaskets from drying out, corrosion or rust and valves from sticking.
Honda motors (utility not outboards) in particular are prone to valves sticking. If a valve sticks open you have no compression and it just won’t start but if it sticks closed it will wipeout it’s nylon camshaft. A little shot of marvel mystery oil will prevent it.
In injevted engines it’ll keep all parts of the fuel system coated and clear, the injectors clean and have all the other benefits.
I use it in my mowers, farm tractors (antiques that still work hard for me, I have 6
) snow blower, backpack blower and tiller.
Incidentally if you suspect you have bad gas in a mower DO NOT put that gas into your car or truck.
Yard equipment can run on crap that a car or truck can’t.
It’d be like shooting yourself in the foot. The repair bill that sour or contaminated fuel can cause will be high. Your looking at a couple of dollars in gas wasted at most, don’t risk it!
Honestly two week old gas doesn’t go bad that quick. I’d suspect one of the following with your mower.
The fuel pickup in the tank may be blocked. Vertical pickups are especially prone to that. The carb may be dirty. There is a small rubber diaphragm that serves as a fuel pump that wears out. Another simple thing that gets missed and can made an engine run rough is that that little pinhole in the fuel cap can get clogged with dust.
I’d suggest checking that and giving it a shot of the marvel mystery oil to the fuel first to see if that doesn’t help clear the dirt out and run smoother. If it’s a few years old I’d change out the fuel pump diaphragm, it’s only a couple of bucks.