BX Choke

BX Tech talk
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mnde
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Post by mnde » Mon Oct 30, 2006 8:00 pm

ellevie wrote:This appears to be from the same source as the pdf link above.
http://www.yaronet.com/posts.php?s=50151
The interesting thing is that it seems to suggest that a sticky choke can be cured by lubricating the waxstat drive rod with a few drops of oil. Might be worth a trying and comparing the before and after required times for the choke flap to reach the full vertical position.
Interesting, because I have done just that and it seems to have done the trick with my autochoke problems!

I took off the body/vacuum chamber and doused the linkages underneath with a liberal helping of WD40 - then I noticed a bit in the Haynes that says to grab the drive rod with pliers and push it into the deflooding capsule as far as possible, then measure the strangler flap opening. By doing this I finally discovered the mechanics of the pull-down system, and also determined that the rod was slightly sticking! As I didn't have much time, I applied more WD and moved the rod in and out several times (I plan to apply a few drops of 3-in-1). But just with this simple fix, the cold starting has improved dramatically and the engine doesn't die suddenly as it was apt to do, even if I held 2000 revs). Hurrah!

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

ellevie
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Post by ellevie » Mon Oct 30, 2006 11:21 pm

=D>
David

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DLM
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Post by DLM » Thu Nov 02, 2006 12:27 pm

Kitch currently has my copy of the Haynes Carb Manual which has overhaul/adjustment instructions, specs and service data for the various Solex and Weber Carbs fitted to BXs (and to other PSA cars which used the same carbs). OK - I'm sure it falls in to the "Book Of Lies" category we're all familiar with but I'm sure there's some useful stuff in there.
Relying on two wheels and musclepower since the last BX (or any car) had to go.

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mnde
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Post by mnde » Sat Nov 04, 2006 9:40 am

Yes, I think there's some pretty useful stuff in there. I once printed out a few relevant pages that were up on that priceless rbwsmith website. I've got a spare Solex carb, ex. Cavmad's bargaintastic 1.6 petrol, that I want to try out all the servicing checks/adjustments on.

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

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mnde
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Post by mnde » Mon Nov 27, 2006 1:35 pm

Just to resurrect this thread...

BX16 1991 Fast idle at cold: In the Haynes carby manual, it says you need to set the fast idle lever by means of an adjustment screw that butts onto the throttle opening mechanism, so that, at 20 degrees C, the primary throttle butterfly is open by a specified amount - c. 4 mm I think - then as the engine warms up, the idle speed returns to normal.

Of course the only way to do this properly is with the carb off the car. But I wondered if the specified opening would correspond with a particular RPM if everything else is as it should be (plugs, leads, dizzy cap in good condition, no vacuum leaks etc)? 1000.... 1200?

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

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Post by jeremy » Mon Nov 27, 2006 2:02 pm

Do you really need to remove the carb? I seem to recall the instructions for setting a Weber on a Ford Cortina 2000 was to use a 4mm drill as a measuring gauge between the flap and the choke and this could be done from the top.

Something worked on that as I recall that in a queue of traffic before the think was fully warm it was possible to get the choke/fast idle to go off and idle very slowly by blipping the throttle, and go back on again with a higher idling speed by releasing it slowly.

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mnde
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Post by mnde » Mon Nov 27, 2006 2:29 pm

Hi Jeremy,

As I understood it, the choke and the fast idle settings are two different things on my Solex.

The strangler flap must open by a specified amount when the pull-down mechanism is activated at cold-start - you set this by checking the gap with a twist drill with the waxstat drive rod pushed towards the deflooding capsule as far as it can go, with the aid of pliers, thus simulating the the action of the vacuum pull-down. This can be done with the carb in situ.

But the fast idle is determined by the opening of the primary throttle butterfly on the bottom of the carb, controlled via a lever and an adjusting screw which you can see near the lower right hand of the autochoke chamber with the cover removed.

Mark.
1982 Citroen GSA Spécial Estate
1997 Renault Mégane RT 1.4e
1991 Citroen BX16 TGS Meteor - gone to Scotland

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Post by jeremy » Mon Nov 27, 2006 4:38 pm

In which case if its adjustable by a screw - adjust it so you get an adequate fast idle when it starts up and doesn't stall as it warms up.

Usual starting point for these things is 1 1/2 turns.

Some tend to scream when cold on auto chokes - which may ensure good starting but doesn't sound very pleasant and is probably not good for very much including the FDV filters - so I'd have thought 1200 was the sort of figure to be aimed at.