Assuming the rest of the tune-up has been handled, valves adjusted, oil changed, and timing set, let's get started on adjusting the carb. Start the car to warm the engine, once the engine is warm turn the mixture screw (depending on the carb it's usually the small screw on the left side.) clockwise til the engine starts to die and then turn it counterclockwise til you get the engine at it's highest idle point then go 1 more half turn out and this should be a good reference point.