Gasoline expanding in Snow blower gas tank due to temperature change?


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Old 04-14-18, 07:50 AM
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Gasoline expanding in Snow blower gas tank due to temperature change?

Apologies for the long post!!

Not so quick history: several snowstorms ago, after using the snow blower, I put it back into the garage. A few days later, when I heard the next forecast for "significant snow tomorrow", I refilled the gas tank. (FYI, The snowblower is five years old, and engine related maintenance has been done throughout the five years.)

The "significant" snow turned out to be approximately 3-4 inches, most of which melted by 11 AM the next day, as the temperature was in the upper-40s. There was no need to use the snowblower.
A week or so later, on a day when temperatures were in the 60s, I walked into the garage and smelled gasoline. I checked around and was surprised to see the top of the gas tank on the snowblower had a light coating of gasoline. I cleaned it up, and figured that was the end of it.
In the intervening couple weeks temperatures range between 30s and 60s. Yesterday, with temperatures slightly above 80, the same thing occurred – smelled gas sought on the snowblower clean it up. I decided "enough was enough" and siphoned the tank down to about half full.

Finally, my question:
Was this caused by the gasoline in the full tank expanding due to increased temperatures, or was it something else?
As always, thanks in advance.
 
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Old 04-14-18, 09:31 AM
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The gasoline didn't expand but the increase in temp caused the vapors to expand.

I would guess the vent on the cap may be plugged somehow causing the build up of pressure to be causing gas to leak!
 
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Old 04-14-18, 10:32 AM
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It sounds like the gas tank was overfilled.... not allowing any expansion room.
 
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Old 04-14-18, 03:08 PM
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You don't want to fill the tank to the filler neck brim (like many of us do anyway). Both Marq and Pj are correct. You should only fill the tank about 3/4's. Then empty it out completely when you're done with it for the season. Allow the carburetor run out also by letting the engine die out from lack of fuel.
 
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Old 04-15-18, 06:14 AM
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Thanks again! I'll check the vent, and fill the tank to a lower level.
 
 

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