Yeah once you start it from cold with the choke closed (black lever pointing to 6 o'clock) and it fires into life then cuts out, you open the choke fully, leaving it open you pull the chord a few more times and it'll burst into life, remaining at idle. The choke must always remain open when you're using it, you won't need the choke again until you're wanting to start it again and things have cooled down when you're not using it.
The throttle arm is connected to the servo, it's the other side of the carb you'll see a chunky adjustment screw. The throttle arm is connected to a rod which passes through the carb (and has the butterfly on it in the middle of the carb), on the end of this rod is a sort of triangular piece which points downwards. It's the bottom corner of this piece which makes contact with the idle adjustment screw. I set mine so the screw just about touches it, very slightly opening the carb. Your LSN may need a tweek to stop the engine from hunting.