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Re: Carb tuning

To: "Chris King" <cbking@alum.rpi.edu>, <spridgets@autox.team.net>
Subject: Re: Carb tuning
Date: Fri, 18 Jun 2004 18:52:09 -0700
References: <1a56a01c4559c$f4b183f0$0a09010a@mail2world.com>
----- Original Message ----- 
From "Chris King" <cbking at alum.rpi.edu>
To: <spridgets@autox.team.net>
Sent: Friday, June 18, 2004 6:30 PM
Subject: Carb tuning

> As I was adjusting the carbs today (after adding heavier springs per
> Daniel1312's reccommendation, and adjusting the valve clearances), I
> noticed something odd, at least to me. If I let the car idle for a
> minute or so, and then rev the motor, there's a small cloud of fuel that
> spits back out the carb throat. That would tell me the carb is rich, but
> it seem to be just fine per the "lift the piston" method. What am I
> missing?

Likely nothing.  There isn't any air velocity to speak of when you first
open the throttle from idle, to suck in any momentary rush of fuel.  This
extra fuel is useful to wet the intake manifold walls to keep the engine
from stumbling.  On cars with an accelerator pump, a good shot of fuel is
given at this same type of moment.

> As an aside, I also noticed tonight that the car idles lower with the
> headlights on (~900 rpm) than with them off (~1200 rpm) 900 rpm with
> this cam sounds like the engine wants to stall, but it keeps running.
> Any thoughts?

Got an alternator on the car?  Takes power to run the lights, so the idle
may well drop a bit.  My car engine will drop a bit further at idle with the
lights on when the wiper delay kicks on!  These things take power, the
alternator is willing to produce amperage, but the engine idle on these cars
are not computer controlled like a new car, so the idle drops a bit when
more electrical items are used.


> Thanks!
> -=Chris

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