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Re: Blanking off choke doubles idle, meaning ?...

To: John Weale <tyre@u.washington.edu>
Subject: Re: Blanking off choke doubles idle, meaning ?...
From: Atwell Haines <carbuff@nac.net>
Date: Tue, 15 Jun 1999 21:21:03 -0400
John,

You may be the 'victim' of multiple problems.

Now that the choke is out of the picture, it sounds as if the
bypass/deceleration valve is bad.  That's a common cause of a 2000 to 2500
RPM fast idle.

Got any gasket material left over?  Blank that b/d valve off and see if
your idle returns to normal...

BTW if you are looking at the Bentley manual, be advised that the pic of
the idle speed screw is misleading.   The spring-biased 'idle' screw is for
the _choke's_ fast idle; the actual idle screw is the slotted headless
screw just forward of the other one. It has a 3/8 locknut surrounding it.
(This drove me bonkers for a while last year during my 'learning' phase.)
Back that off before you muck with the bypass valve.

You won't mess anything up by covering all the choke holes with your
blanking gasket.  And no, I don't know why they want the throttle propped
open, unless its to make removing the choke's linkages easier.

Atwell Haines
'79 Spitfire, converted to manual choke, no beer cans used at all.
Succasunna, NJ USA

"When everything's coming your way, you're in the wrong lane, going the
wrong way."



At 04:53 PM 6/15/99 -0700, John Weale wrote:
>
>       In my quest for a smog certificate, I blanked off the water
>controlled choke in my Spit (using some gasket material, though I was
>sorely tempted to use a bit of beer can just for the heck 'uv it).  Now
>the idle is around 2400 rather than the 1100 it started at. I adjusted it
>down via the throttle speed screw, but am concerned that I screwed
>something up.  When removing the water choke, I did not hold the throttle
>plate open as the manual (dug out after I did it of course) instructs.  
>Any idea why it says to do this?  Is it reasonable to hope that the choke
>was stuck open and blanking it off simply fixed the mixture (it did fail
>smog due to high CO and HC's perhaps this contributed?)(hey, I can dream
>:), raising the RPM's?  Is blanking off all the holes between the carb and
>water choke OK (I assume so, but that's gotten me into trouble before)?
>
>Thanks for any advice!
>
>John Weale


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