<VV> Hard to Start...

[Secular]

  Hi Tony:

  I finally got around to messing with the carbs. I did what you and Mike Stillwell 
  suggested.
   
  Namely, I closed (backed out) the idle speed screw and the idle mixture (all the way in) 
  on both secondaries AND now the car starts right up :)

  In essence, the car now idles nicely on the two primaries but operates on all four 
  while driving. No more hard starting !

  I'm grateful for your help. 

  Regards,


  Tony

----- Original Message ----- 
From: "Tony Underwood" <tonyu at roava.net>
To: <virtualvairs at corvair.org>
Sent: Thursday, October 12, 2006 3:03 PM
Subject: Re: <VV> Hard to Start...


> At 08:18 hours 10/12/2006, Mike Stillwell wrote:
> 
>>  Hmmm, maybe we're on to something. I like to run them
>>about 2 full turns out. If you get bored, try that set
>>up (Secondaries all the way in, Primaries 2 turns
>>out).
> 
> 
> This allows the idle bleed air to come from the primaries only, IF 
> you also backed off the idle speed adjust screw on the secondaries so 
> they don't try to draw any more fuel than necessary from the 
> idle/off-idle circuits.   Then, if you tighten the mixture screws to 
> kill the bleed air on the secondaries, your primary carb mixture 
> screws will function normally, as per "the book".
> 
> Been there done that a couple times.
> 
> 
>> >   oddly enough Mike, I have noticed that the car
>> > idles smoother
>> >   when I turn the idle mix screw all the way in and
>> > then just barely
>> >   open ( @ 1/4 turn) on all four carbs !
>> >
> 
> 
> 
> This is what happens when you run four carbs with idle 
> circuits.    Doing it this way, you'll likely need to adjust all four 
> for the best idle, which gets to be twitchy what with also having to 
> juggle the idle speed screws on FOUR carbs instead of just two, along 
> with their corresponding idle mixture screws... each of which then 
> only requires half as much air through the mixture circuits because 
> you have FOUR air bleeds instead of just two.
> 
> It's important to remember that the mixture screw is an AIR bleed, 
> not a fuel feed.   Tighten it, richer idle mixture, (depending on 
> throttle opening) loosen it, leaner mixture.  It's a combination 
> adjustment... to a point.    If the throttle is completely closed, so 
> that no air passes through the carb venturi, the air bleed 
> effectively becomes pretty much moot.
> 
> To get to what "the book" states, you'd have to completely close (as 
> in back off and/or remove the idle adjust screws) the throttles on 
> the secondary carbs and tighten the air bleed screws all the way down 
> so as to shut the secondary air bleeds off entirely.   Then, ignore 
> the secondary carbs, adjust only the primary mixture screws for 
> smoothest idle and the primary idle adjust screws for the correct 
> idle speed.   The small amount of fuel which will find its way 
> through the secondary carbs from the idle circuits will be 
> insignificant when it's done up this way, and the idle mixture screws 
> on the primaries can compensate for it.    You should be able to get 
> a smooth idle and a steady idle speed this way.
> 
> 
> These are the issues you'll get when you run primary carbs as secondaries.
> 
> 
> 
> tony..