Tampering with adjustments is not a good idea, at least until after you've checked the system for malfunctions.
First of all, if you are starting your car by a normally prescribed procedure, i.e. for cold start-------depress gas pedal once to about 1/3 or 1/2 throttle. This sprays a prime charge of fuel into the intake manifold, it allows the automatic choke to close, and it rotates the fast idle cam to an initially fast idle position.
Immediately after start-up a vacuum signal will pull the choke shutter part way open and it will allow the fast idle cam to retract to a slower fast idle position, but the cam cannot drop to that position until you tap the gas pedal gently and then release it. During the warm-up period the cam will continue to move to a progressively (step-wise) slower idle position until normal idle is reached.
The most likely problem you have is that either your choke pull-off system is not working, or that the linkage to the fast idle cam might be gummed up a bit or corroded so that it no longer moves freely.
I don't have any 300G-specific information, but most of our older cars use a vacuum piston (located within the choke's bimetallic spring chamber) to pull against the spring an open the choke part way. Newer ones have vacuum diaphragms usually mounted to the carburetor body and linked to the choke shaft to accomplish this choke opening.
Adjustments don't change by themselves. If it worked before, something has gone wrong that adjusting won't fix.
Hope this is helpful,
---------- Original Message ----------
From: "Val Jeffers edward1108@xxxxxxxxx [Chrysler300]" <Chrysler300-noreply@xxxxxxxxxxxxxxx>
To: "chrysler300@xxxxxxxxxxxxxxx" <chrysler300@xxxxxxxxxxxxxxx>
Subject: [Chrysler300] 300 G Fast Idle
Date: Thu, 27 Oct 2016 13:16:42 +0000 (UTC)
My G runs around 1800 to 2000 RPM for about 15 minutes until it kicks off down to around 750 RPM. Is this normal ? I don't recall it doing this in the past. I'm a little apprehensive to try and adjust ! Any thoughts appreciated.
; Val Jeffers
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