Re: Gas tank air lock
There are only 2 reasons (that I can think of) that would cause a slow or no fill of a built in fuel tank.
- Non-working vent
- Non-working fill hose
Even if the vent is "working" it may have a tight bend, or crimp, that reduces the flow of air from the tank when it is being filled. The out rushing of air must be at it's maximum to allow fuel to displace it in the tank at the speed it is being pumped in. This is not the same as the amount of air required to allow the engine to run, which removes the fuel at a much slower rate.
A non-working fill hose would be much easier to diagnose as you would have fuel everywhere if it leaked, was disconnected, or if it was kinked.
So my suggestion would be to check out your vent line. From the tank it should run unobstructed to the 90degree overhead bend at the vent thru hull.
To check the hose I would remove the hose (tie a cord to the hose so you can pull it back), inspect it visually, and use a compressor to blow out the inside, there may be an obstruction in it.
The hose needs to be class "A" or "B" fuel hose, rubber, and probably 5/8" diameter.
Also check the fitting at the tank for obstruction and that the thru hull vent is not obstructed. To do this I would remove both for a visual inspection.
I realize this is a lot of work, and may require some adaptation on your part, but it is what I would do if nothing was obviously wrong.
My bet is a crimp in the hose.
You will now receive other, possibly better, ideas.
Have fun.
One last thing, you don't mention your fuel tank capacity. I am assuming it is more than 5 - 6 gals?