engine compartment venting

[cdt785]

Hi. Basic question. Im installing a new vent fan for bilge.. There was always just one vent back there. I have a 17'bowrider with a 3.0 Mercruiser.Should I attach another hose for fresh air and where should I place the end?Middle of engine or down towards the bottom? Thanks in advance

 

[Bondo]

Ayuh,.... Gas is heavier than air, so the suction hose for the blower should be down low, but not in any bilge water,....

 

[cdt785]

Thank you for the reply Bondo. I guess my my question would be I attached 4 inch flex hose on the port sidehole going out the back for fresh air. How long should that hose be and should that go down to the bottom of engine or stay up higher? Thanks