Gas tank, cap, or ghost??

[tcfeet]

Parked my boat 20 days ago after running it 4 or 5 miles.
Walked by it this eve., and noticed gas dripping off the foot.
The tank is a 6 gallon plastic tank. It appeared to be swelled like one will when it sits in
the sun. It had about 5 gallons of fuel in it. The line was still connected to the motor, {06-25 -2stroke}
Are the caps on the plastic tanks vented ? We have not had temp. over 55 degrees since it has been parked.
Any suggestions?
Tom

 

[wrench 3]

Re: Gas tank, cap, or ghost??

Fuel from in-ground storage tanks is at 40 degrees, so you will have some expansion. That and most newer tanks will vent in but not out. It might be an idea to disconnect the fuel line when not in use.

 

[tcfeet]

Re: Gas tank, cap, or ghost??

I think you are right. I just read that the epa had made them change portable tanks in 2011 to include a device to prevent
evaporation into the atmosphere. Maybe the cap has been replaced with one that does't vent, therefore forcing fuel through
the engine ? It does not have the device between the tank and squeeze-bulb.
The 35 year old merc I replaced never had such problems, and never dissconected the fuel line. Then I never used anything
but "real" gas in it too. Them corn squeezings does some weird things...

 

[wrench 3]

Re: Gas tank, cap, or ghost??

Them corn squeezings does some weird things...

I'll have to remember that phrase for future use.
Glad I could shed some light on the situation Tom. Wouldn't want you thinking it was haunted.

 

[rolmops]

Re: Gas tank, cap, or ghost??

Them corn squeezings does some weird things...

Yes it does. When poured into a glass it makes me act funny

 

[rolmops]

Re: Gas tank, cap, or ghost??

Them corn squeezings does some weird things...

Yes it does. When poured into a glass it makes me act funny. When you disconnect the fuel line from the outboard,you may very well have leakage from one of the connectors. Just loosen the fuel cap a half turn so the pressure can escape

 

[MH Hawker]

Re: Gas tank, cap, or ghost??

It depends on the cap, the older ones have a manual vent and the new one have a automatic vent that dosnt work.

 

[tcfeet]

Re: Gas tank, cap, or ghost??

I think I will install a "fuel demand valve" between the tank and primer bulb and try that. Its supposed to eliminate the
problem I had.......
Thanks for the info guys.. Its 9:18 pm so I'm pouring a shot of squeezings in my tank now..

 

[tcfeet]

Re: Gas tank, cap, or ghost??

Ok, I thought of something that might have caused this.. I remember checking the fuel level a few days ago,
and screwed the cap on tight, "but never heard the click".. Suppose it was tight enough to seal the tank, but not enough
to open the "vent"??

 

[robert graham]

Re: Gas tank, cap, or ghost??

You may have noticed that the newer red plastic gas tanks are about twice as thick as the older models....it's so they can survive on a sunny/hot day without blowing up like balloons due to their lack of venting....this is our government/EPA at work. This ventless tank causes some pressure build-up and has caused some fuel leakage problems in some outboard fuel systems. I understand there are some devices that can be added to these fuel systems to help deal with this pressure....But about a 1/4 or 1/2 turn of your gas cap can allow it to breath just enough to eliminate this....

 

[tcfeet]

Re: Gas tank, cap, or ghost??

Yes, I had screwed the cap on tight, but never heard the "click" its supposed to make according to the
writing on the cap. What I would like to know is : When the click sound occurs, does it activate the vent then?

 

[99yam40]

Re: Gas tank, cap, or ghost??

I believe the new ones will let air into the tank so a vacuum will not form while pumping fuel out, but are not going to let any pressure/fumes out due to EPA