Re: Why is their fuel from this fitting while filling the tank?
Since both lines rely on gravity, it does not matter where the vent is in relation to the fill as long as the vent is above the top of the tank. The loop in the fuel line is to stop the infiltration of water back into the tank
It does not matter where the vent is in relation to the fill as long as the
loop in the vent line is above the the fill.
The loop in the vent line will stop the infiltration of water back into the tank, and it will also stop an overfilled tank from pouring out the vent.
If the vent loop is above the fill, the overflow will never make it over the top of the loop before it comes pouring back out of the fill.
When filling a tank it is expected that an overfill will produce a fuel spill at the fill fitting.
The normal person will not be expecting gas to first appear at a fitting somewhat removed from the fill fitting.
When I fill a fuel tank I expect that if I overfill it I am going to get gas all over my hands.
I do not expect that the first indication of an overfill will be gas all over my shoe.
If the vent is just above the
Fuel Tank Top, over filling the tank up the fill hose will cause the excess fuel to overflow out of the vent line.
The over flow will continue to flow out the vent until all the excess gas in the fill hose come down to the level of the vent fitting.
This sets up a bad situation because the user then needs to be filling the tank and not looking at what he is doing at the fill fitting, but looking at the vent fitting to assure that an overfill situation is not happening inadvertently.
*** The normal way of filling a tank is to continue to fill until the fuel pump senses fuel backing up the fill hose and trips the fuel handle auto shut down.
If the vent fitting/loop is below the fill fitting, A fuel spill happens every time. ***
Additionally if the vent loop is above the tank but below the fuel fitting, depending on the geometry, a potential fuel spill can happen every time the boat accelerates on the water or on the trailer.
Fuel rushing back up the hoses in an acceleration will not hit the inside of the fuel cap first, it will go out the vent fitting first.
You could be loosing fuel to the road or the water and never even know it.
A level of idiot proofing should be included in the design, especially if the cost of the safety feature is close to nil.
