I've got to weigh in on the "keep your tank full" approach. I used to do that too... 10+ years ago. But I don't use that approach anymore.
Reasons:
1. These days the ethanol in the gas we buy is more likley to be in the upper end of the range advertised on the pump. That is, the pump will have a sticker on it that says "up to 10% ethanol" and in recent years its there. I just don't want that laying around for months in my tank.
2. I want only fresh gas run through my Yamaha. I am convinced that injector and VST issues with my 115 were caused by old gas. My current 150 will only see relatively fresh gas.
3. Its easy to leave a little gas in my tank during storage and pump it out when I am ready to start fishing again. I get a small fuel pump and get the old gas out... I am guessing less than 10 gallons. That amount easily goes through my lawnmower, weedeater, etc.
4. Price of gas is much more variable than it was 10+ years ago. I am a working stiff and I admit to watching the trends and making bulk gas purchases based on current pricing. A buck per gallon one way or the other makes a major difference in filling up my boat.
5. I used marine stabil for any gas I store more than 2 months. But no matter what, gas deteriorates with time. I do whatever I can NOT to use old gas in my Yamaha, no matter what treatment might be involved.
Just sayin'
