Refilling outboard petrol tank

[thinwater]

thinwater,
I thought to the danger of pressurizing a fuel tank, not so much for explosion as, more likely, for causing unnoticed leaks. Thus I always pump the tank only for refilling the outboard and vent it immediately after. I modified the air tap on this purpose to avoid opening the cap.
It did not came to my mind of the static spark danger. Static charge could be generated by the friction of the pump piston but in this area there is only air, no vapours. To be sure that no vapours come back fom the tank to the pump one could do one or two pump strokes before opening the air tap.
Anyway a mixture of air and vapours is always present in a partially full tank. Indeed problems often arise from condensation water in the tank, arriving to the carburator etc. and this water comes from the air.
Well, matter for thought.

A bulb pump would do the job but would keep a crew busy during all the filling time - rather long due to the low flow rate - and a tap would be needed at the outboard end of the tubing to avoid spilling at the end of the action and the tubing itself would always remain full of fuel.

Long Keeler,
I am afraid that the No spill Spout is only fit for its Combi Can. It should be interesting knowing its working principle but, as with all gear sold on line, very little information is given.

I would add that I also spotted from far away a small car wheel washed up on a beach on the lake. On inspection the tyre turned out to be my trailer's size. Salvaged as spare.

No, leaks are not the reason for the prohibition on tranfering with air pressure. They are the reason boat petrol tanks must have free vents instead of controlled vent systems we have on cars. BTW, it is NOT forbidden to transfer using nitrogen or other inert gas, only using air.

The reason that gasoline is not unspeakably dangerous is that a tank at equilibrium contains a flooded mixture, unable to explode. This is why it used to be so easy to flood a carb by leaving the choke on. So ordinary, except after RAPID emptying, a petrol tank does not contain enough air to explode. But if you pump air in, you change the equilibrium. You create a bomb.

It is safer to turn off the engine and refuel. Transfering flamable liquids with pressure is universally forbidden. There is no way to put a different face on that.