lets talk gas tank fill hose and vents!!

[bob johnson]

so I am assembling my boat now and I have an aluminum permanent tank installed between the stringers. I need to run the fill hose and I have a gas fill cap. The cap has a separate "vent"-"overflow" nipple. Is this nipple for the vent from the gas tank??? or is it in addition to the vent hose from the gas tank( which used to go to a flange -vent mounted to the side of the hull). it would SEEM that once the gas cap is screwed tight...there is NO vent to air.. the tank only has three ports in it. A fill port (1.5" dia), a feed fitting, and a vent port ( 5/8th dia). so if this fancy gas cap's extra port is solely for over flow protection I am wondering how the gas is routed to the tank!!

next question: if you fill the gas hose all the way up the gunnel to the top( 20+ " ABOVE the gas tank) is the vent hose also filling up?????

next question: I looked for SS hose clamps at the hardware store and the box said ALL STAINLESS STEEL clamps. But the hex head on the clamp screw was magnetic( the band was not)... are they using a 400 series SS for the head..or are they lying about the ALL SS???


next question: is it more desirable to have the gas tank fill port on a flat horizontal surface, or better to have on a verticle surface..like the side of the gunnel.

originally it was on the side... wondering if people have an opinion on that... there seems to be pros and cons.

thanks


bob

 

[Bondo]

Ayuh,.... I think yer fill is a combined fill/ vent,... Nothin' to do with over-flows,....

next question: if you fill the gas hose all the way up the gunnel to the top( 20+ " ABOVE the gas tank) is the vent hose also filling up?????

Of course it is, fluids seek their own level,.... Don't try to fill it so full,.....

next question: I looked for SS hose clamps at the hardware store and the box said ALL STAINLESS STEEL clamps. But the hex head on the clamp screw was magnetic( the band was not)... are they using a 400 series SS for the head..or are they lying about the ALL SS???

Never seen one with a ssteel screw, just the rest of it,....

next question: is it more desirable to have the gas tank fill port on a flat horizontal surface, or better to have on a verticle surface..like the side of the gunnel.

Closer to horizontal is better in My book,...

 

[BillP]

It looks like the one that came on a pontoon boat (1996) I had. It was a fill with integrated vent. The fill shut tight but the vent was open to atmosphere like any other vent and you could see where it vented. Mine was mounted vertically on the side so no fuel could enter the boat (which is now regulation). Its hard to tell from your pic.

 

[BWR1953]

All I can say is don't put the fill cap next to a rod holder! I made that mistake about 20 years ago with an old boat and I ended up having a problem due to personal error on my part. Stuck the fuel nozzle into the rod holder and pumped gas all over my deck!

But even now as I look back on the event, it was totally worth it!!