[AT] OT McCullogh chain saw parts

[charliehill]

Thanks Steve.  That explains why my chain oiler doesn't work right any 
longer.  I've been meaning to replace that stretched out o-ring.  Now I 
will..... as soon as I find my gas cap!

Charlie
----- Original Message ----- 
From: "Steve W." <falcon at telenet.net>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Tuesday, December 30, 2008 11:43 PM
Subject: Re: [AT] OT McCullogh chain saw parts


> charliehill wrote:
>> Yes it pretty well has to be vented to some degree to keep the presure
>> somewhat constant.  Luckily this 30 year old McCulloch is built a little
>> better and uses a little less plastic that some of the stuff out now.
>>
>> Do you remember how the old 2 stroke dirt bikes  had a plastic tube run
>> through the center of the gas cap?  I always figured it was some sort of
>> vent line but I never owned one so I don't know.
>>
>> Charlie
>
> Depending on the model it could be a J tube vent or a S tube. They
> allowed the fuel to slosh around and move without giving you a bath. A
> street bike has a vent in the cap (like any tractor) to allow fuel to 
> flow.
> The tube runs from the tank down to a small catch can which is also
> vented directly.
>
> On the chainsaw the vent basically is a one way flap. It allows air in
> to keep fuel flowing but shuts to keep gas from coming out. Most of them
> also have a sintered brass filter over them to keep crud out, others
> have simple screens. Your oil cap also has a vent.
> Both gas and oil are pumped and as such the level dropping creates a
> slight vacuum in the tanks, without the vents it can stop fuel/oil flow.
> Not a good thing.
>
> -- 
> Steve W.
> Near Cooperstown, New York
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