2016 60 Mercury 4 stroke, on pontoon boat, fuel tank has pressure on it when I unscrew fuel cap always.
Bass Pro shop mech says this is ok because a non vented cap is used so water will not get in because of all the water spray in that area.
Does this sound correct?
Thanks
EPA now requires all fuel systems be closed with no vent so that no fuel vapor escapes. That causes pressure on the tank which is normal. However it does require the use of a fuel demand valve on the fuel line. This valve works like a regulator permitting fuel to pass to the engine as the engine needs it but never allows fuel under pressure from the tank to reach the engine.
Skeeterbait, I do have that in the fuel line, I was worried about the pressure on the tank itself or is it ok?
Thanks
The modern tanks are designed for the pressure since they are no longer allowed to be vented.
ok great, thanks
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In regards to pressure- the tanks CAN vent but must remain closed/sealed up to a minimum of 5 psi.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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I see some bilge fires and or explosion's in our future. Would have been a lot safer to vent it thru a charcoal cannister and purge it when runningOriginally Posted by EuropeanAM
Thank You Leon Pugh
Leon- not sure where you're going with that, but PERMANENT tanks will always have their pressure vents situated to release OVERBOARD in the event that pressure exceeds the setpoint. The FDV is not a vent device, it's installed in the fuel supply line.
Portable tanks are the only ones that will vent at the tank (they utilize the cap for this purpose).
Note: These requirements have been in place for almost 7 years now, so it's nothing "new".
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Fuel should never be under pressure in an enclosed area, vented thru a cannister to trap vapors that could have been avoided, Give it few years it will happen
Thank You Leon Pugh
Leon... you do know that many below-deck setups include a charcoal cannister, right?
Not saying I'm a fan of the pressurized systems, but since it's a federal regulation and all boats manufactured with built in systems must comply, I'd recommend some research/learning on what the various systems are comprised of, and how they work before condemning them.
Just something to think and read about....
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
That's just it Don, I know very well how they work as well as what can go wrong with them! Anything behind the demand valve is now a potentionel liquid or vapor leak with thermal cycling. You know as well as I do what the bilge areas look on older boats that are not cared for. Rotten lines, pinched and abraided, wrong clamps etc. May very well still perform ok or not, but leak when hot soaked
Thank You Leon Pugh
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