Do motor covers restrict air flow

[Dignity]

A friend says he was surprised when he left his cowl cover on for a trip that he used significantly more fuel than normal and he takes his cowl cover off (the vented type) Has anyone else trialled running with and without the cover. I have intended to try and test it myself but it's difficult to do a long test run in very similar conditions.

[Noelm]

Had them on and off, no difference in fuel use, the vents in the cover line up with the cowl vents, can't see how it can make a difference at all, unless it's just a travel cover?

[ozscott]

I haven't noticed fuel siddweenxe but some cowls don't do well....paint bubbling with condensation trapped. Cheers

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[Dignity]

Had them on and off, no difference in fuel use, the vents in the cover line up with the cowl vents, can't see how it can make a difference at all, unless it's just a travel cover?

It's a bit like a screen door, restricts the breeze I suppose the theory goes. I couldn't find anything much about it on the hull truth which surprised me.

[Dignity]

I haven't noticed fuel siddweenxe but some cowls don't do well....paint bubbling with condensation trapped. Cheers

Sent from my SM-G960F using Tapatalk

Hasn't affected mine as it does have a lining and it only comes off once a hear when the motor is serviced

[ozscott]

Hasn't affected mine as it does have a lining and it only comes off once a hear when the motor is serviced

Mine had a foam lining and bubbled the paint on my 2000 model Yammy 115 2 stroke. Doesn't do that on my Tohatsu. Cheers

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[Dignity]

Ozcott, mine has a felt type lining. I imagine foam could react with petrol fumes. Some things should never be together, I know rubber and ally aren't happy buddies unless you have a full layer of sealant between them.

[bradsm87]

The cowl is designed to draw air in at the back and it travels around the sides, keeping things cool and in through an intake at the front.

I've logged manifold pressure at full throttle on a T60 and there is very, very little pressure drop from having the cowl on. Any advantage at cruise would be placebo effect.

[Tracker]

140a zuk outboard cover 4 years no paint problems or air restrictions.

[gazza2006au]

The outboards cowling intake is at the rear to stop the outboard sucking water strait into the engine

Only thing i would think of is aerodinamics rather than have a big gush of twiling air like a tornado coming in thru the intake the screen is breaking up thst tornado air flow kind of like myth busters using straws in there air flow tank testing thingy

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[Spaniard_King]

OCA covers have had significant R&D to ensure they don't restrict air flow