<VV> Carter YH choke "blink"

Doug Mackintosh dougmackintosh at yahoo.com
Sun Aug 29 17:15:06 EDT 2010

Yes, I meant pulloff, not unloader. 

As to why I think the blink happens when the choke is fully open, in a VV 
response to a query about a cough on acceleration, Craig Nicol said 
"Acceleration enrichment in the YH happens through the usual accelerator pump 
squirt, but that is the secondary system.  The primary system is the choke 
plate, which for lack of a better term, "Blinks" for a moment when the engine 
vacuum drops at the sudden opening of the throttle. After that, the pump shot 
occurs, which continues the enrichment." I don't think there was any suggestion 
that either the problem or the cause were restricted to cold engine conditions.
-- Doug Mackintosh
Corsa member since 1996
Corsa/NC member since 1996, Virtual Vairs member
Corvair owner 1969-1971 and 1996-on 

From: "BobHelt at aol.com" <BobHelt at aol.com>
To: dougmackintosh at yahoo.com; virtualvairs at corvair.org
Sent: Sun, 29 August, 2010 15:49:24
Subject: Re: <VV> Carter YH choke "blink"

Doug, please see comments below.
Bob Helt

In a message dated 8/29/2010 12:14:41 P.M. US Mountain Standard Time, 
dougmackintosh at yahoo.com writes:
I have read before that the Carter YH accelerator pump delivers a fuel squirt, 
>but that this is preceeded by enrichment delivered when the vacuum drop causes 
>the choke plate to "blink". I understood that the blink is caused by the vacuum 

>unloader briefly letting the choke close partially when the vacuum level drops.

The blink is caused not by the unloader, but by the choke pull-off. the unloader 
is entirely mechanical.

>If I have that straight, can someone explain why there would be a blink even 
>after fully warmed up? 

What makes you think that there is a choke blink after the choke fully opens up 
and is held in position by the thermostatic coil? It shouldn't happen as far as 
I know. Please explain.
I would have thought that the unloader was no longer 
>affecting the choke position once warmed up.
again, you mean "pulloff" I think.

> -- Doug Mackintosh
Bob Helt


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