<VV> Rochester Idle Circuit Inconsistencies

[Shaun McGarvey]

I've dealt with this problem .
I've always thought this was something blocking the idle circuit, be it 
dirt, rust, or even water. Apparently the surface tension of water is higher 
than gas and can't easily be sucked through the small passages in the idle 
circuit.
Methyl Hydrate in the gas tank will help if it's water.
Take the top off the carbs to see if there's crap on the bottom of the float 
bowls. Water pools on the bottom. Add a filter if there's dirt or rust.

yea, Vairily ... Shaun

----- Original Message ----- 
From: <Mikeamauro at aol.com>
To: <virtualvairs at corvair.org>
Sent: Sunday, November 02, 2008 10:04 AM
Subject: <VV> Rochester Idle Circuit Inconsistencies


> I've noticed a propensity for H-Series carbs--early or late--to have
> transient idle circuit inconsistencies; the situation I describe goes for 
> carbs
> thoroughly soaked in carb cleaner, overnight, and then having all passages 
> blown
> out with compressed air, then rebuilt...as-well-as carbs having been  in
> service for some time.  Issue Description: (assumes side-to-side air  flow 
> is spot
> on, as verified by Unisyn) The idle may be smooth for several days,  or
> months, and then all of a sudden idle becomes rough and engine wants to 
> "die"  at
> idle. Simply revving the engine sometimes clears the issue. Otherwise, 
> removing
> air cleaner; revving engine, and momentarily cupping hand over carb air 
> horn
> sometimes clears the issue and idle returns to normal. However, more often
> than not, the required fix is to remove idle mixture screw and squirt carb
> cleaner and/or compressed air into the hole from which the idle mixture 
> screw
> was just removed. Reinstall mixture screw; adjust, and all is well...till 
> the
> next time. Why is this happening? This has been a fairly regular 
> occurrence,
> on two different vehicles, over a number of different carb  rebuilds, 
> using
> different cores, over many years of Corvairing. Has anyone  else observed 
> this
> situation? I surmise flaking may be occurring in  the idle circuit 
> passages, and
> the increased velocity imparted by: revving,  revving & cupping air horn,
> and/or blowing through the circuit may be  dislodging the offending, 
> obstructing
> flakes. Other opinions or ideas, for  a long term solution, would be
> appreciated.
>
> Thank you,
> Mike Mauro
> **************Plan your next getaway with AOL Travel.  Check out Today's 
> Hot
> 5 Travel Deals!
> (http://pr.atwola.com/promoclk/100000075x1212416248x1200771803/aol?redir=http://travel.aol.com/discount-travel?ncid=emlcntustrav00000001)
> _______________________________________________
> This message was sent by the VirtualVairs mailing list, all copyrights are 
> the property
> of the writer, please attribute properly. For help, 
> mailto:vv-help at corvair.org
> This list sponsored by the Corvair Society of America, 
> http://www.corvair.org/
> Post messages to: VirtualVairs at corvair.org
> Change your options: 
> http://www.vv.corvair.org/mailman/options/virtualvairs
> _______________________________________________