I have a OS .46 that is well broken in and it is installed in a Sig Kadet LT40.

I have started having problem with the idle mixture screw backing out. The engine starts to get tempermental in starting and the transition from idle to full power is spitting and sputtering.

This happens after four or five flights.

Readjusting the idle mixture makes everyting fine again.....any ideas on how to keep the screw from backing out by it's self?

The engine is not vibrating I balanced the prop mounts are tight, etc.

Appreciate any help thanks.