There certainly is no shortage of opinions regarding prepping the fuel system for storage. I think that treating the fuel with a stabilizer such as Stabil, Startron, Seafoam etc is important. If you run the fuel out, there is still fuel remaining in the bowl of the carb and elsewhere. So if you still want to run it out- treat it first- or simply don't run it out. Fuel that is exposed to the atmosphere will certainly deteriorate. The buisness end of the fuel system is the carburetor which is either exposing the fuel to the atmosphere via an external or internal vent. You may remove the bowl and drain further should you wish.

This may be a bit anal, but I always add a stabilizer to the fuel which I use for the mower, power washer, edger, de-thatcher etc. At the end of the season of that particular machine's use, I drain the tank into a gas can and run the machine dry. Rather than let the fuel in the can sit over winter, I use it in the tractor for plowing or I poor it into the car's tank and start fresh in the Spring. I have never had a fuel related problem with any of the machines that I was the original owner.

This post was edited by grass1950 on Tue, Aug 13, 13 at 2:34

My approach id different-
I start using Stabil in the fuel the last couple mowings so that I know the fuel is "well mixed with the Stabil". (I'm never sure when the last mowing happens until a few weeks after the last mowing)

I top off the tank INTO the fill neck when putting it away.
Basically, don't allow ANY dead air space in the tank.
Dead air space allows the tank to "breathe" during temperature fluctuations. Moisture laden air get's sucked in, water is absorbed by the ethanol, tank breathes out drier air, repeat.

Springtime and it typically starts 2nd or 3rd pull. 23 year old Honda.

Heh, Heh I dose the fuel with MMO. Come the end of the season. I park it in the shed and use the shutoff to run the carb out of fuel. Same as I do after after every mow. I dont even take out the battery. Since I have started doing this routine, I no longer have to tear down the carb every spring BTW,. I use 87 octane with 10% ethanol in it.

My appraoch is running the system dry. Since ethanol was introduced I have always used Stabil added to my fuel all year around, which includes my Snowblower.

Before storing I run the carb dry, as it begins to sputter I choke it attempting to burn every possible drop. Next I remove the gas tank and drain it. Some gas always seems to remain, so being anal, I use my compressor to blow out any remaining fuel.

Next I clean or replace the air filter and spark plug to have it ready for the season. Then I shoot a few drops of oil into the cylinder and pull the starter rope a few times to lubricate the cylinder walls.

Last I insert the spark plug and I pull the cord just to the point where I feel resistance. This is top dead center which closes both valves. It serves two purposes, the first being it relieves the tension on the valve springs, the second being it reduces the ability for condensation entering the cylinder.