vented or not vented?

[jesusn]

sup i have a 70hp motor on a 17ft boat and my question is does the fuel tank have to be vented or what , whats the diference if its not a vented tank oposed to a vented one? the one i have now isnt vented and afeter some use is starts to compress its self and suck down in the middle is this a bad thing ? should i relive the presser before restart? or is this just normal or should i invest in a better tank?


thanks any help would be apreciated

 

[Bifflefan]

Re: vented or not vented?

You need a vented tank. When you suck out the gas there has to be a way for air to get in and replace the volume that is removed. Or you get just what you said, the tank sucks in. This will cause un-needed wear on the fuel pump and will at some point make it stop running.
You may be able to get a vented cap for the tank and that will do the trick.

 

[Vic.S]

Re: vented or not vented?

Two line tanks are not vented .. they are pressurised but they are the very old ones phased out around the time if the Pilgrim Fathers I think!

Other tanks must be vented. Some have an automatic vent others have a vented cap. They must be vented to allow air to get in as the fuel is drawn out. If air cannot get in eventually your fuel pump will not be able to draw fuel out!

 

[jesusn]

Re: vented or not vented?

my tank has one line with quik disconects but no vent not even on the cap its a plastic six gallon got it at kmart is it ok to not tighten the cap all the way to let air in or is that a bad idea?

 

[jesusn]

Re: vented or not vented?

my bad the cap is vented dont know why i didnt check b4 thanks guys