Technical Carb mixture adjustment

[Most Easterly Pandas]

How do I adjust the fuel/aix mix in the carb on the Sisley?

Managed to get her running now, and is fine except at idle when warm. Just want to adjust the screw thing. Isn't it screw it in all the way and then out one compleate turn and then half a turn

Jon.

 

[pandamaniac]

Theoretically you are correct.
However engine wear will mean the old one and a half turns from fully in won't always be right.
Set the tickover speed to low but stable with the engine hot, turn the mixture screw out until the engine runs at its fastest (but before it slows down again for being too rich), then turn in 1/4 to 1/2 a turn and you will be about right.
Re-set tickover screw to the tickover you want.

Drive for a while and check plug colour, should be light brown.
Pandamaniac.

 

[Chas Uno]

As above for mixture adjustment, Pandamaniac suggests the exact same steps I would use when adjusting the mixture on a Weber 32TLF.

Don't forget though that the mixture screw is damaged very easily by people who screw it fully in too tight when adjusting, which damages the end and renders it somewhat ineffective. Also note that it only adjusts the mixture at idle and has little/ no effect once the throttle butterflys are opened.

 

[Most Easterly Pandas]

Ta guys. Another question quickly, to save starting a new thread. 91 Sisley 4x4, what type of ignition system is it? Went to get new dizzy and arm today and need to know if its magnarelli or Ducilia. Its got the type of amp with the metal heat sink on the distributor if that means anything

Jon.

 

[Chas Uno]

Ta guys. Another question quickly, to save starting a new thread. 91 Sisley 4x4, what type of ignition system is it? Went to get new dizzy and arm today and need to know if its magnarelli or Ducilia. Its got the type of amp with the metal heat sink on the distributor if that means anything

Jon.

I'm not entirely sure as I've only ever seen one non Magnetti Marelli dizzy, which was fitted to a 1988 white Uno Bianca (999cc 45S) that Louie Bee in the Uno section bought a few years back.

I think you can tell be the distributor cap colour:

White = Magnetti
Black = Ducellier

I think as well that the Magnetti used the silver finned ignition module bolted on it whereas the Ducellier has a flat black unit (really not sure on this one as it was a few years since I saw it )

 

[Most Easterly Pandas]

I'm not entirely sure as I've only ever seen one non Magnetti Marelli dizzy, which was fitted to a 1988 white Uno Bianca (999cc 45S) that Louie Bee in the Uno section bought a few years back.

I think you can tell be the distributor cap colour:

White = Magnetti
Black = Ducellier

I think as well that the Magnetti used the silver finned ignition module bolted on it whereas the Ducellier has a flat black unit (really not sure on this one as it was a few years since I saw it )

Ta, I got both black and white dizzys working on it :bang: so that ones out the window because I always thought you could tell by colour also until I brought this 4x4 with about 3 different coloured Dizzys with it

Has the silver finished ignition module though, so think its Magnetti as I'm almost sure the replacement amp for the last Sisley which was the other type of ignition system was Ducellier.

Ta.

 

[Most Easterly Pandas]

Right, changed carb as I've convinced the one on the Sisley from the last donor 750L is US'ed. Only when I realised that the Sisley was now running as crap as the 750L was that I assumed it must have been the carb.

Changed carb and she seems to be running alot better.

When cold though there seems to be a miss fire when accelerating/revving.

Think I've located the cylinder, but the reason I still need to find. I've put new HT leads on her, New dizzy and rotor arm that I brough from motor factors today, and she's beginning to sound alot better apart from the misfire.

I've a vid that I took on the phone (excuse noise, engine sounds alot better in person!) and I seem to have one spark plug checker flashing dimmer. Not angle of camera, when moving head about its the same.

I've swapped plug flashers and this one is always the same. Is it likly to be getting a weaker spark, causeing the miss on acceleration?



Jon.

 

[totnesmonster]

Have you checked/ changed the jets on the carb over to the proper 4x4 ones? They're slightly bigger than non 4x4 ones even though the carb body is the same. Just remove the air cleaner box (10 mm nut) and there's two in the top of the carb. Probably worth blowing them through anyway!

cheers,
Mike

 

[default_user]

Have you checked the plugs? It may be as simple as a duff plug.

 

[Chas Uno]

YouTube - Spark plug strobe check 1990 Sisley 4x4

Jon.

Looks like you've got a rave going on at the back of your engine!

 

[Most Easterly Pandas]

Have you checked the plugs? It may be as simple as a duff plug.

Could be, I've got plenty of new ones floating about (the advantage of buying service kits in bulk), I'll change it and see

Looks like you've got a rave going on at the back of your engine!

lol, tell me about it, kept seeing them out of the corner of my eye and having mini panic attacks thinking the engine was alight

 

[purple haze]

As you know Jon i changed the carb on my Sisley and it now runs perfect..No hunting anymore...What Totnes said is right..i was going to swap the jets over...(my donor carb is from a 2wd 1000cc)

But it seems to run fine so i'm going to leave well alone!!!...plug and lead do look suspect..sure you will sort it...