<VV> Choke Coil VS Pull Off - was ambient

[Frank DuVal]

Well, only if you start up and quickly go to full throttle. ggg

The choke pull off works all the time there is manifold vacuum, which 
only goes away at full throttle.

To quote Bob Helt: "Anytime the engine is running, either at an idle or 
at speed, there will be manifold vacuum at this port. Thus, the choke 
will be prevented from fully closing anytime the engine is running."  
Quoted from his carburetor book, pg 39.

The port where the choke pull off is connected is a rather large (by 
carburetor standards) hole straight to the intake manifold ( i.e. below 
the throttle plate).

I do agree in use that the choke pull off is no longer the primary choke 
plate positioner once the engine has warmed up to where the choke coil 
is holding the choke plate open.

Frank DuVal

On 1/16/2011 5:58 PM, Bill Hubbell wrote:
> Don't have the whole thread on front of me, but the choke pull-offs only function when the throttle plate is nearly closed. As you open the throttle wider the vacuum feed to the choke pull-off falls and it ceases to function. It really only comes into play at start-up.
>
> Bill Hubbell
>