Tuning the Weber 32/36

Today i started my truck up for the first time after removing all the EGR equipment, installing the Weber carburetor and Pace setter Header. Besides being VERY loud from the open header the engine seamed to be idling very high and I am unable to understand how to tune the Weber Properly. I have read this article
and still don't understand how to tune the idle properly. My truck is automatic so would you suggest installing a temporary tach to be sure the idle is set at the proper RPM? Does anyone have any tips on how to get the Weber tuned that isn't stated on the mazda truckin link?



I understand the lower screw is the idle mixture adjustment and the other is the idle speed screwn but even fully tightened the idle speed screw never touched the throttle lever so really its not adjusting anything.

This is my first vehicle with a carburetor so all help would be appreciated!

Ok, the reason the idle speed screw does not touch is because the carb is still on what is called high idle. When the choke is on, the RPMs are raised up (there is a separate adjustment for high idle speed). As the engine (electric choke) warms up the high idle cam starts rotating to a lower high idle speed. Once fully warmed up then the carb relies only on the base idle speed setting.

Also a temporary tach would be a great idea until you get things set. High idle when cold should be around 1,200 RPM. Low idle should be around 600-700 RPM.

Also, the three screws on the gold colored ring are holding the white choke housing in place. If you loosen the 3 screws a little you can rotate the white housing. One direction will make the choke stay on longer. The other direction will make the choke stay on less time or if you turn it far enough it will turn off completely. Also, you will need to "blip" the throttle when rotating the choke as the high idle speed is on a stepped cam which does not rotate unless you take pressure off the adjusting screw.

Thanks for the quick replies!

My truck would idle up with the factory carb when it was cold but would idle down once put into drive or warmed up so the current cold idle must just be sounding VERY exaggerated to me because the Header is open. The high idle screw was not touching the throttle lever when the vehicle was not running either. Should i start the truck and let it warm to the point where it will idle down and then adjust from there? It is cold out but the vehicle is stored in a heated area and will not be driven until optimal operating temperatures have been reached. To adjust the high idle setting would i turn the screw that's supposed to make contact with the throttle lever? I would honestly prefer to completely eliminate this high idle if possible.

I only plan on driving the vehicle 2 blocks from my temporary shop back to my home garage where the rest of the build will be completed. Is it possible to have dangerous air to fuel mixtures and lean out to the point where the engine can be damaged because of improper adjustment on the Weber?

As for the air/fuel mix you should be just fine. The idle mix setting is not going to burn up your motor, just make it so it does not idle. I would suggest you rotate the choke so it is not working, start the truck and let it worm up, then adjust your normal idle speed with the parking brake on and the truck in drive. You should be fine after that for your 2 block drive.

Alright do you know if i have to rotate the choke counter clockwise or clockwise to turn it off? does the vehicle have to be running to adjust the choke until it turns off? Is my normal idle speed adjusted with the screw that makes contact with the throttle lever? should i be adjusting the idle speed until it reaches the rpm of 1200 or 600-700 or am i completely off here.

Thanks for your patience!

Turn truck off, remove air cleaner. Choke plate should be closed. Loosen the 3 screws enough for you to turn the white choke housing. Make note as to the current location of the housing, then turn 1/2 turn either CW or CCW. If you turn it the correct direction the choke plate will open up. Once it is open, tighten the 3 screws back up ( not to tight).

Start truck and allow to warm up. Once warm, put in drive (with e-brake on) and adjust idle speed down until engine dies, then give it a 1/8 to 1/4 turn back in and you should be good to go.

Do you suggest always leaving the choke off or only for this first tuning?
To hook up a tach to these engines can i just run a wire off the green disdributor wire as you would do with any other import?
Is it possible to eliminate the high idle so you only have the low idle setting?

By adjusting idle speed do you mean adjusting the screw that makes contact with the throttle cable plate?

I just want to be sure my engine is operating at safe parameters before its driven

Thanks again

No problem. FYI, the main jet is mostly responsible for air/fuel mixture when you are driving. You don't have access to that so.... no problem. A dirty / plugged air filter will make a rich mixture but yours is new so again, no problem. At this point your biggest concern will be making the truck idle correctly when at a stop sign/light.