How are these vented. I have these on my Nordic. I think they are the older ones though. Mine have the spring, rubber and a plate inside the flip top. I cannot see how they actually vent. So I drilled small holes on the side of them. The holes face away from any incoming water. If I do not need the holes and somebody can explain how they vent then I will tig them up. Thanks.
  T.J.
again I think mine are older.

there is also the possibility that your tanks have vents in them

there is also the possibility that your tanks have vents in them

Nope, no vents in these tanks. When I refurbed the boat I cleaned them and there is only a feed with the tube that acts as a pick-up. What I really want to do is take the tanks out again and cut the small feed set up out (ala hole saw) then make a round plate that will have a -10AN fitting welded to it with a larger pickup tube to match. Along with that I would also weld in a 1/4" npt bung to the round plate and then weld the round plate to the tank where the original stuff was. Sounds like a lot of work but all good in the long run.
T.J.

Hey TJS I think I stubled on your websight with your boat rebuild. Post it up for others to see very cool indeed.

Thanks Blue. I will but my hunk of crap hosting company is junk. It is down again. I will post it when it comes back up.
T.J.
Ok it is back up now. Make sure you visit both pages. I have tons more pics but I am too lazy to keep on creating more pages right now.

http://www.tjsperformance.com/jetboat_tech.htm

I agree with oldsquirt, that is where they vent, the extra holes were not needed    Mark

With the stock as installed engines (around 300-330 HP)the venting thru the filler is fine, with higher H.P. an external vent is needed. Not sure? make a speed run with the tanks near full and note the speed and fuel pressure (install a temporary gauge if you need to), then unlatch the filler and do it again, be careful, don't try this in rough water, and don't forget to relatch the cap. No speed or pressure change and you are good to go, if there is a change, add the vent. Coast guard regs call for a 5/8" hose and vent with a screened opening. Kind of overkill unless you have 1500 HP or so.....  But it does make the tanks easier to fill with an auto shutoff nozzle at the gas station, especially if your fill hose to the tank is long or at an angle.  TIMINATOR

On my boat I had those same fills, and external vents that dump outside the hull.