Join Date: Nov 2009
Location: georgia's toe-nails of the foot hills
Re: Adding afuel Cutoff valve
The dealy on top of the tank is a vapor capture device so you don't vent unburned raw fuel into the atmosphere. It should lead to a carbon canister that will abosorb some level of fumes(vapors) and hold them until the engine is started. After startup, the fuel vapor will be sucked out of the carbon, and fed to the engine.
I always store my fuel with the vent cap closed. It will build pressure, when the temperature changes and some fuel lighter fractions turn to vapor. It is called 'vapor pressure' for a reason, and will change (vp) depending on seasonal mix. More light fractions for winter start ease in colder regions, less in summer.
I don't want vapors to gather in the garage, so I always(99.9%) close the vent upon shutdown. Dunno what the cap shown above will do if you tip the Snapper on its butt.
FWIW, the gas tank will deform into a thinner version of itself if it is shutdown warm, and the temperature drops. So much it fell out of the bracket when I was replacing the boots last week. I must take it out into the sun to soften the tank and get some good vapor pressure to blow it up back to 'normal'...
simplificate & add lightness
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