Right ive got a 2.0 zetec on twin 45 weber carbs, all jetted correctly from the previous owner and RR-ded at 170bhp running fine.
but ive just been tinkering as the idle was rough as hell, and noticed when i lifted the carbs up the engine picked up speed.


so, i got my spanner out and tightened up the misab plates and rubbers, the idle raised, so i screwed down the idle a bit more.
i continued doing this until the engine rpm didnt increase anymore.


now i have the problem that the idle screws are at the top and the engine is running at ~ 3krpm on idle with no more ajustment on the idle screws. the engine is running 100x better than it did before,
but how do i reduce the idle further????

 

they are meant to be a bit loose on the manifold

 

your supposed to use feeler gauges between the thackery washers and gap them up. (cant remember setting though)

make sure the throttle cable isnt keeping the butterflies open a tad, as that will make it rev obviously. i would undo the cable and slacken it right off.

are you adjusting the idle mixture screws, or the SINGLE idle throttle screw?

 

using the SINGLE idle throttle screw!
the cable is loose enough, theres a little play in the cable before it starts opening the butterflies so its not that.

i know about the thackery washers they still have at least 1mm or just slightly less than 1mm of the mounting rubbers showing between the cups, they were very loose when i first got to them.
i cant remember the setting nither but the nuts holding them in are still relativley finger tight in comparison to anything else you bolt up =)

 

its about half a mm if i remember rightly, but it sounds like yours are sealed up anyway if the revs raised.

have you checked to see if the butterflies are bent, or the linkage is not keeping them open?

 

they dont look bent, when i put some pressure upwards on the idle ajuster (throttle linkage) i can get the engine to idle at 1000rpm, but thats with the bottoms of the arms touching the base of the carbs where the single idle screws screw into.

so it is possible to get the idle that low, but it seems the linkage is to blame, but i thought the linkage was on a square nut to the butterflies, so when it turns it turns the (axle) for the butterflies to open on???

so do i need my butterflies re-spacing for idle, so they sit a little more closed when the square pin that goes through to control them is in the same position?
=)

 

do you have adjuster rods on your linkage? might be that.

 

the rod in the middle????





the linkage is touching the body of the carb, as you can see from the bottom shot theres no more ajustment left in the idle at all

 

yeah, they look backed right off actually. weird.

 

i know the stops are on a square shaft so they canne be ajusted without opening up the carbs.

bump---- anyone???