Mi16 Idle Mixture Screw

[AndyJ 1]

As above, which way do you turn it for rich/lean?

[Ethos 0]

I believe it's in to make the mixture richer and out to for leaner...

[Anthony 1,003]

Yep, Ethos has it correct:

 

Clockwise = richer (higher CO)

Anti-clockwise = leaner (lower CO)

 

Aim for about 1% CO or so and that's about right in my experience

[AndyJ 1]

Cheers guys should really invest in a co meter at some point...MOT this afternoon so im just going to lean it out as far as i can without it hiccupping.

[Anthony 1,003]

Cheers guys should really invest in a co meter at some point...MOT this afternoon so im just going to lean it out as far as i can without it hiccupping.

Lean it off until the engine note changes and it becomes slightly more "chuggy" than normal, and then wind it in a little so the engine note settles - that'll get you in the right ballpark, and should certainly pass a MOT emissions check like that unless there's something else amiss. Normally if you ask the MOT man nicely, they'll let you tweek the CO on the emissions machine, although tbh Mi's don't seem to be anywhere near as sensitive to idle mixture as 8v's on Jetronic are and will idle/behave just fine on a suprisingly wide range.

[AndyJ 1]

Yeah ive noticed much twiddling doesnt make much difference. Im a bit worried it might not pass on HC as well cos it likes to misfire at idle, which is something else I need to look into. but fingers crossed! (also convincing them to do a non-cat test on it could be fun according to the previous owner...)

Edited March 23, 2009 by AndyJ

[AndyJ 1]

...after all that it failed on a flippin brake hose! I miraculously had got it spot on 1%CO.

 

And I nearly didnt have a test at all, the guy reckoned he had to test it as a cat car cos he had to go by the year of the shell, which was just plain wrong. It was only after i'd given up arguing and said fine i'll go somewhere else that his boss came out and dragged me back in as i was driving away lol. Fair play he was a decent guy, just got the wrong end of the stick from the mot computer.

[Tom Fenton 1,542]

All you need to do is refer them to the MOT testers manual which every station has. In there, you will find there is a section regarding emissions testing regs, essentially it goes on the ENGINE and not the car. However the onus may be on you to prove the engine age.