Carb idle mixture screw, end play?

[N429EM]

While adjusting the low end mixture, on my OS .46FXi, I noticed the needle would push in and spring back out. This makes it almost impossible to adjust, while the engine is running. I'm just wondering, if there's too much end play, and something has begun to come loose.

Any thoughts?

Thanks,
E J

[ivanc]

It's dangerous to adjust the idle needle when the engine is running as the screwdriver is very close to the prop.

It is normal for the throttle barrel to have some side play, otherwise it might get stuck to the throttle retaining screw. There is a spring behind it and its purpose is to eliminate that side play.

If you still want to practice unsafe procedures (at your own risk and which I do not recommend!), open the throttle to approx. 1/3 and adjust the idle needle - the engine won't die then.

Ivan