Hello all. I am new to this so please forgive me if I don't do this the right way, or give all the information needed. What I have is a 1974 Ski-Doo 400 TNT. I am looking for information leading to the factory adjustments of the carburators. While trying to get it started, we pulled the chokes on and soon after it started and got running pretty good, we shut off the chokes and it ran for about 30 seconds. Now we started it again and I can keep it running with the feathering the throttle but the smoke comming from the exahst was more that I feel should of been. I feel that there might be an adjustment that needs to be made on the air/fuel mixture. But here is where the problem lies. Which of the 3 screws do I adjust and how much? There is one screw on the left side which I feel is the idle adjustment. One screw on the right side which I assume is the air/fuel screw, but what is the one on the front that is in the float bowl? What does that adjust. Now the carbs are a Mikuni and were bought aftermarket, so they are not bought with the sled. I can take pictures and send them if that is any help with this. Thank you in advance for any help with this.