Re: [OMC-Boats] cowling venting

From: JEFF DOOD <jdood@...>
Date: Tue, 22 Jul 2008 08:34:43 -0700

AH - ok, makes sense now. although diminishing noise seems to be the
least concern with about 1/2 the boats i see (hear) at the boat ramp
every time.

and so if the thing on top is a spark arrestor, not an air cleaner,
where do these engines get their air for combustion - shouldn't there
be an intake somewhere? not disputing, just wondering

so i guess i could put a grill in my cowling, and it would just be
louder and maybe a little less likely to explode on starting due to
better fume venting. but it won't run any cooler!

actually another question - are gas fumes heavier than air? if
so, where i want to put the vent won't help the fumes at all. either
way, i always run the blower regardless.

On Jul 22, 2008, at 7:03 AM, D. F. Julien, AIA wrote:

> Hi Jeff
> Engine noise is probably the reason for the tight compartment. If
> you put a
> grille in the back cowling, facing forward, you'd greatly increase
> your
> awareness of the engine noise.
> Not that it changes your argument, but that round thing on top of the
> carburetor is a spark arrestor, not a filter. I guess the
> presumption is
> that boats don't go down dusty roads much during operation.
> -Doug Julien
> ----- Original Message -----
> From: "JEFF DOOD" <jdood@...>
> To: "Evinrude & Johnson Boats of the 1960's and 70's"
> <omc-boats@...>
> Sent: Tuesday, July 22, 2008 12:19 AM
> Subject: [OMC-Boats] cowling venting
>> kind of inexperienced with boat i/o motors. here's something i
>> don't get.......why no venting in the cowling? i happen to
>> have a
>> Deluxe, but i think it's the same story with other boats as well.
>> - You are supposed to vent the fumes out with a blower before
>> starting.
>> - the top of the carb has an air cleaner intake just like a car
>> (although small)
>> yet my particular cowling seals up pretty tight and seems like it's
>> designed to not let any air get in. it does have a smaller grill in
>> the back of the engine compartment, but minimal. So why aren't
>> cowlings (or atleast mine) vented like crazy with air grills all over
>> the place? it just seems like it would A) make the engine run
>> better
>> by providing more available fresh air intake, B) make the engine run
>> even cooler with air flow taking away some of the heat , and C) make
>> it easier for the accumulating fumes to get out of the cowling
>> without
>> having to rely on the blower.
>> I have a perfect spot right on the front of the cowling for a nice
>> big
>> chrome vent, but i don't want to be cutting any holes without knowing
>> for sure first.
>> _______________________________________________
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Received on Tuesday, 22 July 2008

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