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Hissing while unscrewing the gas cap

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Hissing while unscrewing the gas cap

Old 01-02-2020, 10:19 PM
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Default Hissing while unscrewing the gas cap

My 2014 Sea Hunt with a f150 yamaha died while going WOT. While poking around the engine rigging I noticed the primer bulb was completely collapsed. I unscrewed the gas cap and it sucked in a lot of air. The person who owned the boat said that undoing the gas cap when to fill the boat up causes a hissing sound. Is that normal? does your boat hiss, like it is sucking air when you unscrew the gas cap?
Old 01-02-2020, 10:47 PM
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No, the tank should be vented.
The good news is your tank does not have cracks or bad gaskets where water can get in.
(the tank vent on my Cobia is in the lid itself.)
Old 01-03-2020, 02:19 AM
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Sounds like your tank vent is clogged
Old 01-03-2020, 06:11 AM
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It shut off because the tank was under a vacuum.
Old 01-03-2020, 06:25 AM
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If my cat hisses at me, I'll slap the dog shizzle out of it. Better teach that boat some respect and tear it a new vent hole.
Old 01-03-2020, 06:28 AM
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When fuel bulb collapse and the tank hisses when you open then the vent line is clogged/kinked
when the fuel bulb colapses but tank is not hissing then the fuel pickup/line to the bulb is clogged

The tank vent serves to release the air while refueling but also to suck in ar when using gas while enine running.
Check the front of the fuel tank where you can see the filling hose, there is usually also the vent line and the fuel level sender.
Undo the thinner vent line hose and check if free
Mostly som insects built a nest inside the fuel vent on the outside of your boat usually somewhere there where the filler cap is.

Old 01-03-2020, 02:10 PM
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Your 2014 boat's fuel system would have the newer mandated emission devices, most likely including a carbon canister that easily gets compromised if you fully fill the tank . You may have to empty or replace a flooded carbon canister.

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