Engine compartment vents

carcraze

Petty Officer 2nd Class
Joined
Mar 4, 2010
Messages
141
Hi all

I have a new to me 88 Mirage and I replaced 1 of the 2 blowers and was doing some vent line replacement. I noticed that the boat has 1 pair of vents per side, 4 individual vents in total. All the vents face forward, ie force air into the compartment when running. My prior boats have always had half face forward and half face rearward. The front vent on each side has the vent lines (2 per vent) attached carb level forward of the motors. The rear vent has 1 vent line in the corner mid height and the other down into the bilge just center of the motor, with the other side the same but just center of the other motor.

In my thoughts and what I know of my other boats I would think the rear vent on each side should be swapped side for side so they face rearward to act as a vacuum while running with the forward one the way it is now for positive pressure, am I thinking of this wrong?

Thanks
Mat
 

Rocky_Road

Lieutenant Commander
Joined
Oct 8, 2008
Messages
1,798
Re: Engine compartment vents

Mine are half forward, half rear facing...always made sense to me!

Happy boating!
 

lowkee

Lieutenant Commander
Joined
Dec 13, 2008
Messages
1,890
Re: Engine compartment vents

Mine are both forward facing. If you are underway (there is wind to inject into the cowls), I don't think fuel in the air will ever be an issue anyhow, since you are supposed to purge the air via fan before heading out.

Grasping at an analogy, sort of like steering the landing gear after takeoff.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,581
Re: Engine compartment vents

Half forward half backwards. That way you have a flow of air through the bilge.
 
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