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Fuel Vent VS Fill Orientation

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Old 03-15-2020 | 09:59 AM
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Default Fuel Vent VS Fill Orientation

I'm currently in the process of ordering materials to replace my fuel fill and vent hoses. While researching the purchase online I came across a article that stated the vent thru hull fitting should be mounted above the fill. Another mentioned always 2' above the water line and it doesn't matter if it's above or below the fill. Currently and from the builder the vent is lower than the fill by about 1'.

I'm curious as to what the OSO community's inputs are on the orientation.

Thanks!


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Old 03-15-2020 | 12:38 PM
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Never seen a vent that was higher than the fuel fill.
You do need to put a loop in the vent tube hose. The loop should be above the vent hole.
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Old 03-15-2020 | 01:36 PM
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And keep the vent tube constantly higher than the vent fitting on the tank... if it swamps down lower, sloshing or overfilling the tank will hold a bit of fuel and block air flow - same principal as a plumbing trap...seems simple but have seen this problem come in on brand new boats (painfully slow filling)

FYI, combo fill vents/ the vent is on the side or btm of the filler where the fill nozzle goes in and on bigger boats the fuel fill on on the deck (some cruisers on the gunwale) and the vents are lower on the side of the hull. Shorter, sweeping runs (no pinch points) all for faster fuel fills and air to vent out of the tank...

Last edited by speicher lane; 03-15-2020 at 01:46 PM.
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Old 03-15-2020 | 01:52 PM
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Pic shows some previous and current requirements, but just showing for routing purposes only


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Old 03-17-2020 | 06:56 AM
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Originally Posted by speicher lane
And keep the vent tube constantly higher than the vent fitting on the tank... if it swamps down lower, sloshing or overfilling the tank will hold a bit of fuel and block air flow - same principal as a plumbing trap...seems simple but have seen this problem come in on brand new boats (painfully slow filling)

FYI, combo fill vents/ the vent is on the side or btm of the filler where the fill nozzle goes in and on bigger boats the fuel fill on on the deck (some cruisers on the gunwale) and the vents are lower on the side of the hull. Shorter, sweeping runs (no pinch points) all for faster fuel fills and air to vent out of the tank...
Mine's correct; however, fills with fuel and blocks venting and when the temperature builds starts blowing out pick up seals etc. trying to vent. Happened last weekend for the first time in 5+ years of ownership. Lesson leaned not to fully fill now.

I was curious to know if moving the vent to over the fill would alleviate this issue. I guess not considering the fill and vent positions on the tank would not change.

Last edited by Tractionless; 03-17-2020 at 07:16 AM.
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