Gas Cap vents

[MakoMike]

Originally Posted by macojoe

My boat has a perfect vent, but when the tank is full and I have the trailer up a little on the trailer to keep the water draining, the vent gets blocked by gas, The result is leaking gas out the vent.

Putting another vent in is just going to make the problem worse! You're best bet would be to just fill the tank a little less so the gas level doesn't reach the vent line.

[macojoe]

Van My boat has a vented cap, it has a small line running next to the fill hose, that connects in the cap assembly, but I still get a little leakage when it starts getting warm out. I think that is just from expansion.

Could that be the only issue?
Can you just not "top %$%$%$%$, leaving a little room for expansion?

Thanks Van!
Yes it is all from expansion, and the fact that when the boat is tilted up it blocks the vent hole in the tank as the vent is in the rear of the tank.
The vented gas cap, does it only work when there is a hose from the tank to the cap, or does it vent its self?
I agree drilling the tank os not the thing to do!

Putting another vent in is just going to make the problem worse! You're best bet would be to just fill the tank a little less so the gas level doesn't reach the vent line.

Thanks Mike, Why would adding a 2nd vent be worse?? If I added one to the front it would not be blocked when boat is tilted allowing for it to vent, right?

I know that it being to full is the case, but even if I don't fill till it tops off and tilt the boat up it blocks the vent in the rear.
Why they ever vented it in the rear is beyond me!

[TheSpecialist]

Originally Posted by macojoe

Thanks Van!
Yes it is all from expansion, and the fact that when the boat is tilted up it blocks the vent hole in the tank as the vent is in the rear of the tank.
The vented gas cap, does it only work when there is a hose from the tank to the cap, or does it vent its self?
I agree drilling the tank os not the thing to do!



Thanks Mike, Why would adding a 2nd vent be worse?? If I added one to the front it would not be blocked when boat is tilted allowing for it to vent, right?

I know that it being to full is the case, but even if I don't fill till it tops off and tilt the boat up it blocks the vent in the rear.
Why they ever vented it in the rear is beyond me!

Just like the old fruit punch cans, the punch would flow out slow with one hole but add the second and it flows like Tiger Woods, because you release the vacuum..

[beamie]

If the main shape of the tank is fore and aft the vent really should be coming from the forward end of the tank now. Hopefully it is.
check to see if the vent hose is hanging low in the bilge causing a "slug" of fuel. If so run it as to not sag. Can the vent be moved higher? If this happens on the trailer is it going to happen out at sea when the boat is trimmed up?

[macojoe]

The vent is in the rear of the tank, not forward. and the hose runs along the top of the tank, up the side and out under the rub rail.

I have no use for 100 gal of gas, I have been out 35 miles off Chatam and back cod fishing and only used 35 gal gas. Now with the 4 stroke I am sure I will not use any more.
I just like keeping it full all the time so gas is not a issue were ever I want to go!!

I am going to pull the deck plates when the rain stops and see again if there is something I can do??

[Van]

[QUOTE=macojoe;758512]
The vented gas cap, does it only work when there is a hose from the tank to the cap, or does it vent its self?
I agree drilling the tank os not the thing to do!
QUOTE]

I am nearly 100% sure there is a second small line that goes into the tank right next to the fill. I think these are welded to the tank. I'm not sure where it really vents to within the cap assembly. I will uncovering soon (I HOPE---back issues) and I will get a good look and let you know.

[MakoMike]

Originally Posted by macojoe

T
Thanks Mike, Why would adding a 2nd vent be worse?? If I added one to the front it would not be blocked when boat is tilted allowing for it to vent, right?

I know that it being to full is the case, but even if I don't fill till it tops off and tilt the boat up it blocks the vent in the rear.
Why they ever vented it in the rear is beyond me!

Right now with the vent blocked the gas is being held in the tank (somewhat) by the vacuum between the gas and the tank, if you put another vent in the gas will flow freely, via atmospheric pressure from the tank. In other words, you'll spill the excess out of the tank much faster if you put another vent in.

[zacs]

If you go to a vented cap, you don't have to drill another hole. Just move the vent line from the current vent to the cap. done. Then you will have a vent on the side of the boat that doesn't do anything...

[macojoe]

thanks zacs, but the issue is the back vent gets blocked by gas when boat is tilted up, so I need a second vent up front so when tilted it vents.
I am waiting for a new cap i ordered on line and see if that is going to help