Bilge vent blower fan
 

My bilge vent blower finally kicked the bucket and I picked up a new one today. Never payed and attention before the old quit but do I want to draw fresh air into the bilge or pump the bilge fumes out when the blower is running?

Blow bilge air/fumes out. Keep hose close to the bottom of the bilge fumes are heavier than air.

you want to pump the air out. Fuel/ Gas Vapor is heavier then air. It will rest in the bottom of your bilge.....if you have enough fumes and there happens to be an electrical spark then BOOM! You want to suck the air of the bottom of your bilge and let the cleaner air on top fill that void from the top. Make sure you have an appropriate hose attached to reach near the bottom of the bilge.