Help with Hitachi Carb idle mixture setting?

[s'ko]

I have a 82 BRAT, EA81 w/a Hitachi Feedback Carb

 

Someone messed with the idle mixture setting.

 

Does anyone know what it is suppose to be?

 

Thanks

 

BW

[swiftt]

14.7 to 1

 

air to fuel ratio.

[monstaru]

ifyou don't have a meter, that means,seat the idle mixture screw lightly(all the way in)not tight,but just to where it starts to get tight.then back it off about two whole turns.start the engine,let it get warm ,have someone watching rpms and if you have to have it pass emissions, do not go below around 950 rpms,if you do not ,put it where you want it at.it is a touch and go type of thing.you may get different responses to rpms if you have rebuilt it, cleaned some of it but not all,etc....

[s'ko]

Thanks for the quick response:

 

I have to pass emissions. I do not have a tach so how can I determine the RPM w/o one?

[Snowman]

You basically have to guess at the RPM if you don't have a tach. Just set the idle speed to whatever it likes the most.

 

For setting the idle mixture. Get your idle speed about where you want it, then adjust the idle mixture screw to the setting where the engine idles fastest. Then adjust the speed screw until it's back down where you started. Now adjust the idle mixture screw again. Repeat this process a few times, then turn the idle mixture screw in until the RPM drops just a tiny bit. This is apparently what you want for passing IM. Afterward, feel free to adjust back to where it idles best.