Is an even idle possible ? or often not ?

[hoogerbooger]

Just wondering if I'm chasing an unlikely dream ?

Last Oct was the best I've had it idle (not that it's been running that often over the years) When warm it had a pretty good low even idle, except that every 20-30 secs it'd have a little dip/hesitation, then go back to an even idle.

It's a 1965 B40 Star 6v; standard Lucas 4CA/AAU; with a new Amal Concentric.

So is the occasional slight hesitation at idle indicative of an issue that ought to be fixable, or just something I need to accept as par for the course ??

[DAVE BRADY]

Hi,

You may need to tweak the air screw a bit as it may be a tad weak.  Do you have a 'Colortune'?
With one of these put in place of the plug you can see the colour of the mixture as you adjust the screw.

Dave.

[hoogerbooger]

No colourtune (and not likely to get one) Idle set with pilot screw and slide stop screw...as per Amal instructions.

I tinkered a few times in Oct to get the best idle setting (having sorted an air leak in the exhaust)...There was no setting I found that removed that occassionL flutter. Seemed fine at higher revs and pulled nicely.

( having added a choke I'm finding it harder to set the idle  but it seems to be hunting a bit now so suspect another air leak somewhere...... but this is a separate issue to my question on should it always be possible to get an even idle)

[iansoady]

I usually find that having the airscrew on the rich side gives better idling and pickup. Just 1/8 turn or so inwards from the "correct" position. But of you have an old carb, you'll never get it perfect.