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Roger.
I am no Stromberg Carb specialist, but from
what you describe it appears NOT to be a idle mixture problem you
have.
It is more that the mixture is too lean in general.
Providing it was not too lean just a while ago I would suspect dirt or water in
the gas.
One thing I noticed recently is that if you have
some water in the gas and it makes it to the carb, it can have that effect you
describe. ( I just had that too) It take a lot of running up & flying
to get all the water out of the fuel system.
Second thing can be that you have a leak at
the mixture control or bowl gasket that allows atmospheric pressure into the
carburetor bowl. The bowl is normally vented into the carburetor throat. A air
leak alters the mixture causing a rich or lean mixture. Which brings me to
the third possibility . It happened to me and was not visible at
all.
An Induction air leak at one of the following
locations: Hoses, Cracked intake pipes, loose flange bolts, loose plugs in
intake port, loose intake tubes in Lycoming engines, punctured flex tubing
connecting the carburetor to air ducting. Slight air leak in induction system
you are usually able to adjust initial idle but rough in 1,000-1,500 rpm range.
Large leaks into induction system, usually unable to throttle engine down below
800-900 rpm.
The info above is Courtesy of Sacramento Skyranch).
I hope this gives you an idea on how to
troubleshoot. By the way, The A65 is using the same Carburetor as the C85, just
different jets are used.
Good luck - Hartmut
----- Original Message -----
From: "roger anderson" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, December 20, 2003 6:51
PM
Subject: [COUPERS-TECH] Lean Idle
Mixture
>
>
> As long as I'm asking, let me ask another question. With a Stromberg and a
> C85, with this sudden really cold weather, I seem to have a lean idle
> mixture issue. With carb heat out she's smooth in taking throttle and does
> a smooth mag check. With carb heat in, stumbles, very rough and large mag
> drop, and will even quit at low rpm. I opened the idle mixture screw a full
> turn without any noticeable improvement. Could this be a float issue.
> This 'Coupe is new to me, being an Aeronca guy also with an A65 Chief.
> Thanks again...Roger
>
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