Modelle
Tom and Ira have given you the tricks to balance those carbs. I
suggest that additionally, in fact before you do much else, check that
you have adequate pre-load on the throttle mechanism so that the
butterflies are forced shut when you lift off the accelerator. I don't
know how your left-hooker setup is all connected but on the Euro model
there is a short rod (adjustable for length) between the bellcrank and
the carbs. You need to check that there is sufficient upward pressure
to force the butterflies shut once the accelerator is released. If
not, and there is slop in the linkages, the engine will not idle or
run properly regardless of what you do. Adjusting the rod length is
simple and all that are needed are a couple of 10 mm open-ended
spanners/wrenches.
Just thank your lucky stars that you're not working on one of the
modern electronics-infested Alfas. We had a huge dump of rain here
recently and my Alfa GT 3.2 V6 decded that the driver's door was open
so kept flashing that message on the check console while I was driving
along. Because this car has a neat trick of lowering the window
slightly to make door closing easier by releasing the pressure, the
window kept going down an inch and then up as the door locks clicked
off and on!!! Happy days! :-) It's a fun car to drive and remarkably
trouble-free but I could do without all the electronic complications.
Regards All
Les in Wellington, New Zealand where it's Winter
Date: Sat, 6 Jun 2015 15:58:57 +0000 (UTC) From: [email protected]
Subject: [alfa] Re: weber balance Gentle Alfisti, A brace of DCOE4
carbs are proving difficult to balance and I want to get them just
right. So I cobbled-together a manometer from two vertical plastic
tubes and rubber stoppers and am drawing vacuum from the brake booster
inlet and the mirror side opening inlet on the adjacent carb. I
fiddled with this contrivance all morning and I still cannot get the
carbs to exhibit equal vacuum. Please, Digest, tell me if the opening
of the carb butterfly by means of the central balance adjusting screw
will increase the respective vacuum in the system downstream from the
opened throttle plate. Or is it the other-way-around? In other words,
will putting the throttle plate on it's idle stop ( fully closed)
increase vacuum at the downstream port? Does the brake booster air
valve effect the results of my comparative balance test? Thank you one
and all. modelle 105.04 gd e-mail me directly for pictures of the
manometer rig. ------------------------------ Date: Sat, 6 Jun 2015
09:14:18 -0700 From: tom sahines <[email protected]> Subject: Re:
[alfa] Re: weber balance Best way to set the balance is to remove the
cover screws for the progression holes. Carefully look through the
center progression hole and adjust the IDLE screw so that you can see
the edge of the butterfly centered in the center progression hole.
Then carefully adjust the central balance screw until both carbs
butterflies are in exactly the same position. All four ports should
align the same, if not then the throttle shafts are twisted or the
progression holes were drilled wrong. Reinstall the progression hole
covers and start the motor. Now adjust the IDLE stop screw to get the
idle correct and you should be good to go. Dont forget to check to be
sure that you are getting full throttle when the gas pedal is
depressed to the floor. I find many cars get only partial throttle
because of excessive carpet padding. On Sat, Jun 6, 2015 at 8:58 AM,
<[email protected]> wrote:
------------------------------ Date: Sun, 7 Jun 2015 11:15:37 +0000
(UTC) From: ira kaufman <[email protected]> Subject: Re: [alfa] Re:
weber balance the procedure is to have the adjusting screws
completely free.make sure both front and rear are completely
closed.if one of the front set is not the xact same as its' mate
there will be no adjusting possible.and ditto for the rear set.if all
are closed properly.screw back the center adjuster first the the
double adjuster screw.now screw in the double adjuster which engages
both front and rear till it just barely kisses it's tab.now check if
all are completely closed.there is a certain screw cap in the top of
each of the four the see with a light where the butterfly sits.only
now can you start adjusting.turn each idle screw in gently till it
sits then turn it out two turns.if the car does not start turn in the
middle adjuster till she starts then when she's warm turn the screw
back till the idle is 900-1000 rpm.now and only now can you use your
vacuum gauge.you check front and then rear and if they are not in
line you must turn the double adjuster (where the little spring sits)
a quarter turn at a time anf then check after each adjustment.it may
sound complicated but once you do it once or twice it's a piece of
cake.another factor is the fuel pressure cannot be more that 5psi. On
Saturday, June 6, 2015 7:00 PM, "[email protected]"
<[email protected]> wrote: Gentle Alfisti, A brace of DCOE4 carbs
are proving difficult to balance and I want to get them just right.
So I cobbled-together a manometer from two vertical plastic tubes and
rubber stoppers and am drawing vacuum from the brake booster inlet
and the mirror side opening inlet on the adjacent carb. I fiddled
with this contrivance all morning and I still cannot get the carbs to
exhibit equal vacuum. Please, Digest, tell me if the opening of the
carb butterfly by means of the central balance adjusting screw will
increase the respective vacuum in the system downstream from the
opened throttle plate. Or is it the other-way-around?B In other
words, will putting the throttle plate on it's idle stop ( fully
closed) increase vacuum at the downstream port?B Does the brake
booster air valve effect the results of my comparative balance test?B
Thank you one and all. modelle 105.04 gd e-mail me directly for
pictures of the manometer rig. -
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