I am trying to adjust my stock nikki carb and need help on how to set the a/f mixture. I don't have any fancy gauges or anything, I was just wondering if there was a way to set it kinda in a general way, kinda estimated. Any help would be appreciated.

Thanks,
Chris

 

Before attempting, you should first chech all the basic tune up adjustments such as: dwell, ignition timing, and spark plug condition. Also, verify that there are no vaccum leaks due to disconnected or leaking hoses. Then, if these symptoms persist, the next step, for a Mazda built from 1979-1982, would be to have the idle mixture checked with an HC/CO analyzer at a dealership or diagnostic center. The reason: a HC/CO analyzer is an extremely expensive piece of equipment and the adjustment procedure is complex.

However, for a Mazda built from 1983-1985, the idle mixture can be checked with a dwell meter. First, disconnect the check connector for the air/fuel solenoid; second, connect a dwell meter for four cylinder engines between the check connector and the engine; and lastly, the meter should read 32'-40' on 1983-1984 models and 20'-70' on 1985 models. If you do not obtain these readings then adjust the air/fuel mixture screw.

 

what is dwell?? i got it on my nifty timming light but it just goes off the scales when i selcet it..

i always thought it had to do with the valves in them other type of egine.. but i think im way off the mark.

 

I thought dwell was the amount of time the points are either open or closed...I cant remember...I think its closed.

~T.J.

 

go out and buy an autometer A/F gauge, go get a n o2 sensor, get it welded in your header if you have one and hook it up. Very useful..

 

Set your idle speed screw to 750 RPM.
Adjust the mixture screw till it idles the highest.
Readjust your idle speed screw so that is at 750 again.
Readjust the mixture again.
Now clockwise the mixture screw about 1/4 turn or so. This gives your idle a little richness that the emission control system needs to burn the nasties up at idle.
It's not necessary to go rich if you've done away with the rats nest. Running lean at idle won't make the engine too hot. Running excessively rich will carbonize your plugs, though.

 

dwell is the time the points are together.

it is the time the coil has current.

 

A good rule of thumb on a Nikki carb if you get totally lost. is all the way in and then back out about 3 1/2 turns

dwell is for points , whoever asked it, you dont use that setting ona timing gun

 

If the A/F ratio is, say 11.3:1 on person A's car, that wouldn't be any more rich or lean on person B's car would it?

 

Ok, Thanks. Does any body have pictures of different gauges, and how to hook them up? Also, isn't there an oxygen sesor in the factory manifold? If so, can I use this one and where is it located? Also, what is the recomended A/F mixture for our cars?

Thanks,
Chris

 

Ha! I made this into a thread of its own and I got answers!! Click here