Re: Is a blower needed?
I know this is a bit late but I would like to add a few points.
There is a difference between the smell of gas and gas vapor. You cannot get the smell of gas to ignite if you wanted to. Gas vapor is actual 'fuel' meaning it has oxygen present to burn, either by compression or the temperature was raised to create vapor. I know all of you here have heard the wives tale or witnessed a match being thrown in a can of gas, nothing happens.
Vents more than anything help to keep the bilge area a bit cooler which could help prevent fuel vapor.
There was a post about fuel vapor in cars just settling to the ground. Autos have an EVAP system which takes the fuel vapor that tries to leak from the gas tank and settles it in a canister to later be purged back to the tank in liquid form. Its an emissions thing, which is why your check engine light comes on when the gas cap is loose.
I guess my point is, if i open a beer, Im going to smell that beer but that doesnt mean there is beer in the air.
So why does an I/O need a blower and an outboard doesnt? Because the I/O has an entire engine running and building heat in the same compartment as the fuel cell, which can create fuel vapor. The heat an outboard produces has no effect on the fuel cell.
