MACTONITE

Been toying with the idea of scooping my hatch to get more air to my Merc 600 SC's, but not sure which way to face them, Forwards or Backwards? I see people doing it both ways and can't seem to find a pattern? Which is better?

MAC

betitbig

I'm thinking about adding one also and wonder forwards or backwards?

Where can I get one like in the picture?

bobonthis

I think usually when the scoops are facing backwards they are just getting rid of excess heat but when they are facing the front they are releaving the heat through venting. We had them facing the front plus it just looks better, I could not find any pics I will try to dig some up I did find some video though but you can barely see them but it did work good for us on a 29 fountain.
http://www.putfile.com/media.php?n=Mvc-003v40

bobonthis

Here is the only pic I could find of the scoop.

800XCR

iTrader: (2)

I have a pair of used scoops available.

Sydwayz

iTrader: (1)

You will have to be careful of the scoops pulling in TOO much air, and trying to remove your engine hatch. Since we are really not talking about ram-air systems here, the rearward facing scoops will give you the more ventilation and fresh air and heat escape you are looking for, without significantly adding noise to your cockpit (as opposed to forward opening). Rearward opening also keeps you from getting a huge splash onto the top of the engine, but most of us are fair-weather boaters; not out in such conditions where the top of the engine hatch is going to be getting so wet, as in rough weather, water over the bow, or racing conditions. I'd go with rearward scoops, with maybe a few vent holes punched in the non-open end of the scoop for through ventilation. Billet Marine also makes some nice finishing bezels for this application.

vette131

they are much louder facing forward. if you face them forward it would be a good idea to put pressure release flaps
in the back of the hatch.

ECeptor

I'm not sure about this, but I assume you want a slight vacuum on the engine compartment so any gas fumes don't get pumped back up through your bilge into the cabin or other parts of the hull. I think forward facing scoops would pressurize the engine compartment.

For sure, forward facing would be much louder like someone mentioned above.

MACTONITE

800 XCR- pm me with info on your used scoops, or you can reach me at (810) 721-3203.

I am running Mercury Racing 600SC's with dual carb set-up. Motors always seem to run to rich, thought more air couldn't hurt. Powerquest only has rear vents under the back end of the hatch, which would probably work as relief vents. Are these difficult to install?
Mike

MnFastBoat

Quickest test is to crack your hatch 1/2 to 1inch while running
Any increase in rpm will tell you right away if yuo will benifit from more air.
When I had my Cat first built the engine bay was always hotter then hell.
Only vents were on the transom unnder the back of the hatch.
When I would crack it open an inch I gained 200-300 rpm
I then had scoops built by Advantage and installed.
I will say they allow the needed air flow.