idle and mixture screws

[xpress]

can someone help a brother out and back their screws out and count the clockwise quarter turns back to where you set it, from all the way out until it stops turning so i can have a reference, i figure quarter turns since the hand's range of motion likes quarter turns. obviously would be good if your mog has been set by a gas analyser or a colourtune or something, can we compare where our set screws are? i ask this because i think my mog's running a bit rich and would like something to compare it to. also, i think she's drinking a bit too heavily and i need to save the pounds. i have a gas analyser might dust it out and try it, it's an old hawk one, any tips for using it? does it need warming up?

[chrisryder]

the basic starting point for the mixture (the big nut under the carb) is 'wind it in all the way, then wind it back 12 flats'. that's normally a good place to start, but if your needle or jet are worn then that will make the mixture richer.

do you know the purpose of the little plunger on the body of the carb, just by where the float chamber attaches? when the engine is warm, press (or effectively lift as it is upside-down) the plunger and if the revs rise and fall back to tickover, you're mixture is perfect. if the engine dies, it is too weak. if the revs rise and don't fall, it's too rich.

or, after a good run, take a plug out and see what colour it is. you want a nice very light brown colour.

the other screw, for tickover speed, is very difficult to get wrong. just dial in the amount of revs you want! do remember that once you get in and put your foot on the clutch, the extra resistance will slow the engine down. so don't set the idle too low, as the clutch will make it cut out!

[bmcecosse]

It's not possible to give a definite answer to something like that.....every engine is different. Just twiddle them until it idles at the correct speed - and as evenly as possible!