Can water get into the fuel tank vent knob of the outboard motor?

Brian,

I've never actually used a Honda 2HP myself, so I looked it up on the web and found the manual (http://marine.honda.com/Products/modeldetail/BF2)

First, the vent knob must be open in order to run the engine.  This is to allow the fuel to flow into the engine.  And since you need to be able to run the engine in the rain, the knob must be designed to prevent rainwater from entering the fuel tank.

It looks to me that they recommend closing the vent knob after using only to avoid evaporative loss of fuel.

So I wouldn't worry about water in the tank.  Just check your fuel level to make sure you have enough fuel for your next usage.

Glenn

Thanks, Glenn.

Leaving a tank vent open overnight is not something to make a habit of.  I found out the hard way when my outboard wouldn't start.  I took it home and drained the tank into a jar. I got a layer of gas floating on top of a water/ethanol mix that wasn't good stuff to start a motor.

In my case the problem was a crack around the filler-cap thread.  During the day the air in the tank heats, expands and some escapes.  During the night the air in the tank cools and the damp outside air is sucked in.  The moisture either condenses or is absorbed by the ethanol in the gas.  After a few weeks you end up with a layer of water at the bottom of the tank.  A new fuel tank cost me $60 but it was worth it.