Zenith Carb Adjustment

[Plow Away]

Wanted to see if anyone knows the proper adjustment for a zenith carb going on a Farmall model A. I need to know how many turns out for the fuel air mixture, idle screw adjustment and so on. I"m in the process of rebuilding the carb but i don"t have an idea on where to set the screw in parts. Thanks for any help.

 

[old]

If you have a GOOD kit it should tell you the starting points if a cheap kit your lucky to get any info. Most say idle set at 1.5 turns out from bottom and main jet about 2-3 turns out

 

[Dick L]

The idle air adjustment screw is just that (idle only adjustment screw) As long as the engine is running above idle it is out of the circuit and you are running on the power jet side.

Just turn it out a turn or two. That adjustment is set in conjunction with the butterfly stop screw on the back. Running above idle you set the stop screw so that it will keep running. you then work back and forth between the two screws to make it run slower. you repete this until you get to the slowest idle you can get with the engine still running. You can actually start the process with the screw turned all the way in or with the screw in your pocket. If that carb has a power jet djustment it would need to be out about two and one half turns. When it starts on about half throttle it can be adjusted open or closed some to smooth it out. After Idle is set open the throttle all the way and the adjust the power jet to the higest RPM and then turn it back in until you here a slight slow down. I redo this setting a coupla times or more to make sure I am hearing it correct. Best it can be done without being under a load.
I just came in from setting an Oliver 70.