I have a force motor will that matter, since I already have it winterized and stored for the winter will less than 1/4 tank.full, with a good stabilizer, especially if there is ethanol laced fuel in the tank. Besure to run it a bit, for the stabilized fuel to reach all the parts of the fuel system.
I will follow my first decision and leave whatever gas is in the tank and just add a sta bil and just wait for the spring and run it then. This is my first boat and want to make sure I have everything in tact and know the ins and outs when it comes to boating.There are lots of threads on here about it, and no matter what ANYONE tells you, there is no right answer... Even manufacturers are split, you can find one example where merc will say full, and another where they say empty. (in the world of internet forums, there are a number of holy wars that are impossible to win. Full vs empty tank is one of them!)
Personally, my philosophy is that why even tempt fate. I don't have to worry about the gas in my tank going bad, because I haven't bought it yet. (in other words, as empty as possible, with stabilizer dumped in prior to emptying it so it mixes and distributes through the fuel system.) That has worked for many years without problem.
I forgot to mention the motor is a force 4 cyl 2 stroke outboard.I fill my tank in fall - last run of the year. Let it sit all winter.
In spring - right before I use the boat I siphon all the gas out and run that fuel in my truck.
I add new fuel from gas cans to the boat. I'd rather run the older fuel in my truck and always run fresh fuel in the boat.
The truck has not complained yet.....