This was what I thought. Everything listed above - battery, ground connections, charging, fuel filters - all stuff that could do it & honestly, they are just basic maintenance that should be checked anyway. I am going to say the vent tube is where I would look outside of carb or fuel pump work.
I have used Seafoam with great results. I know it has the nasty stuff in it but I use it so infrequently it doesn't produce negative effects. Kinda like, do you smoke 3 packs a day or do you have a cigar once a month.
