OMC fuel tank (How does it vent?)

[James_D]

I have an OMC plastic fuel tank in perfect original condition with gauge which came along with engine and boat, the tank has Evinrude fitting same as on engine, the filler cap has metal/brass chain to prevent cap coming off but no screw type vent as fitted on my other tank, how does this work? seller advised me to just loosen main filler cap which must allow 30ltrs of fuel to spill out when underway, any adeas, should I drill cap or does these type of fittings also vent the tank? thanks for help. JBD /forums/images/graemlins/confused.gif

 

[ValleyForge]

These tanks are pressurised right ? so don't work if you vent them.

 

[Cloven]

Some of these vent through the push-on connector at the end of the fuel line. Perhaps yours is one of these. Only works when connected.

 

[James_D]

Thanks for replys, If fuel pump is drawing then I would imagine it causes vacum in tank? hence need to vent? unless it does vent through the fitting?entire set-up is original and perfect as new condition, I can't see a company making such a product where the cap had to be loosened (safety reasons) does anyone own such a tank? any other comments ideas please, JBD

 

[dmayes]

I had a metal OMC tank that did vent when you connected the fitting. There was a spring loaded plunger on the fitting and if you pressed it you would hear the gass release.

 

[Superflid]

Some old tanks worked off air being pumped into the tank (from a breather in the crankcase) in order to pump the fuel to the engine, if it's one of these it'l look like there are 2 pipes connected side by side instead of just the normal 1.

 

[James_D]

Many thanks Gentlemen, same fitting on tank as at engine, (Evinrude), which is 2 pins one is fuel valve, spring loaded pin idea other pin does nothing other than support fitting? and only one fuel line tank to engine, I could send picture or post here if I knew how? thank you again, JBD