Because you live in a humid area the slight rust problem may always be a bit of a problem?? As to the fuel working during the summer but not in the winter did you fatten up the high end a little?? As the weather here starts to cool down from about 100 and it gets to the 50s I have to start opening up the high end a bit at a time. From summer to winter all my engines have a four click difference on the high end or they will start going dead stick on me. It's not a problem with my fuel.