Outboard Motor treatment??

[PolarBear]

The problem with storing any fuel with ethanol, is that eventually the ethanol will absorb condensation, alcohol and water mix, and when the alcohol is blended in the fuel, it will mix. Products like seafoam help stabilize the fuel, but even then, it will have a shelf life. The most important thing is to make sure your fuel likes are clear of the fuel, your llines and bowls empty. Even with a stabilizer like stabil, you can still get build up, and condensation. The proper way to store fuel is to top off your tanks. Seafoam is great because it breaks down the varnishes and carbon build up n your systems, and can help the fuel clean the inside of the motor, but personally, I like to drain my tanks (start my season on fresh fuel, no worries), run my motors on some good clean fresh fuel, get the engines warmed up, remove the fuel source, and let the engines consume whatever fuel is left in the system until the motor dies, and once out of fuel, spray fogging oil into the intake and cylinders while cranking the engine. Remove the battery, take it inside, and drain your lower unit, if you have an inboard, don't forget to pull the caps on your heat exchangers and coolers to remove all water capable of freezing and busting the ends on your coolers.... I also use a primary fuel water separator like a racor, I will have up to 3 fuel filters on a has engine

That's how I've done my boats before, now I have a 14 footer with a 50hp outboard, which gets used year round, so no winterizing for me anymore

Spot on!  This is exactly how I have been doing it for 35 years and it sure saves a lot of headaches.  Like said above, make sure that all of the water is out of the pump and run the trim and tilt is all the way down to relieve pressure on the unit.  I have had great luck spraying Fluid Film in the carbs, cylinders and on the exposed electrical connection inside the motor cowling.  It really helps with corrosion.  Not many boats have them anymore but for some reason if you do have fiberglass fuel tanks NEVER use or leave ethanol fuel in them.  Ethanol will cause the resin to dissolve, separate and can destroy your motor.

[MADMAX]

Seafoam and ethanol free from Cenex

 

[b23]

If you have a smart phone there is an app you can get called "pure gas" that'll tell you where nearly all the  places are to get non ethanol gas.

I'm in complete agreement with those that do not store there tanks, for extended time, full.  Unless it's in a air tight sealed or a positive pressure sealed system, it's venting out and your fuel is degrading and or drawing in moisture. 

My boat was always in our shop and I always capped off the vent.  It helped keep the fuel from degrading as well as kept my shop from smelling like gas.

Something to keep in mind with regard to pure gas vs blended fuel, it's not so much that blended fuel is bad but because it has alcohol in it, it draws moisture much more rapidly causing it to degrade faster than fuel that is not blended.  If you are buying your blended fuel from a source that sells a lot of fuel and always has "fresh" gas, you likely will not have any trouble. 

Also, alcohol blended fuel will act like a parts washer in your fuel system so if you've been running only pure gas then have to switch to running blended fuel, if you have any build up in your tank/s the blended fuel can give you fits because its knocking that stuff loose and sending it through your system.

I'd run your tanks as low as you can get them and add a little Stabil to what's left.  If you can run the system dry, even better.  Pull the plugs and fog the cylinders is never a bad idea if it's going to be sitting for awhile.

[whitey]

I will run my threw the winter. Plus Stabil is important if you use regular pump gas.