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RE: Weber carburator setup

To: Spridgets@autox.team.net
Subject: RE: Weber carburator setup
Date: Mon, 23 Feb 2004 13:12:11 -0800
Hello,

The thing, is that you can get the car to idle properly with any of the 2
screws at any position (ie: fix one, ajust the 2dn)... And I understand
that...

My problem is that if I leave the throtle idle were it ought to be (ie:
close to 0/not open linkage), Then I need to open the idle niddle mixture
more. And If I do that, then I run too rich!

To run at an ok leanness (can I say that?), I need to screw more the
throttle, and more or less cut the idle mixture screen (leaving only the
progression orrifice acting). This leans stuff good at all speed up to 2500
rpm... However, it make for a rough idle...

I change my idle jet to .45, and now my throttle is more or less close and
my niddle is much more open (normal)... My idle is much smother, I have
however not yet checked the richness yet, but I suspect that it will be
better :-)

Do you have a similar setup to mine? What jets are you using?

cyrille

-----Original Message-----
From Peter C. [mailto:nosimport at mailbag.com] 
Sent: Monday, February 23, 2004 12:11 PM
To: DE-BREBISSON,CYRILLE (HP-Boise,ex1)
Cc: Spridgets@autox.team.net
Subject: Re: Weber carburator setup


Cyrille,
         If the stop screw, the one that moves the linkage, is open more 
than 1/2 turn, then the carb goes into the transition phase, and is using 
very little of the idle circuit, the screw that goes into the carb body. 
That may be why you can almost close the idle circuit screw.
         Generally, the car should run with the linkage stop screw in about 
1/2 turn from the point where it makes the linkage move. The needle valve 
should be about 3/4 - 1 turn out from where it bottoms. Idle speed is 
adjusted with the needle valve screw. On DGV Webers, virtually the entire 
mixture required for idling passes through this needle valve orifice. Often 
the mistake folks make is using the throttle stop screw as the idle speed 
adjustment. It isn't. Opening that screw a little too far permits more 
negative pressure to act on the transition orifices which are differently 
metered.
         This is contrary to how many carbs are adjusted, and is a source 
of confusion.
         I would suggest you re-install the original jets and try this.
         Hope this helps.
         Peter
=====
At 12:31 PM 2/23/2004, you wrote:
>Hello,
>
>I have a Weber DGV 5A (32/36) carb on my 78 Midget.
>
>I know that it is running too rich (emission, black plugs, smoke,
backfiring
>...)
>
>I went to a friend's place and he has a cool TRANSPARTEN spark plug that
you
>can place to replace an plug in your engine and SEE the spark, especially
>how yellow/blue it is! Really cool toy!
>
>Ok, so here are the results of the test:
>
>In order to be OK, I had to:
>Change the primary jet to 1.30 (from 1.40)
>COMPLETLY close the idle mixture (and increate the IDLE speed in order to
>avoid the engine stalling)!
>
>This seams to give a much better mixture (emission WAY low, plugs much
>better, no smoke, no backfiring)...
>
>However, I am not happy with the Idle setup and I plan to change the idle
>primary jet from the standard .55 to .50 or even .45...
>
>Does anyone has a similar setup and can tell me how their carb is tuned up?
>
>Thanks, Cyrille






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