Ronald,

The OS.46FX is known to be particularly rich in the mid-range.

Even after adjusting the idle needle for spot-on transition from idle, it will be too fat at part throttle settings, will run at a four-cycle there and if you go quickly from a prolonged 1/4-1/2 throttle, down to idle, or to full power, the engine will stutter and often, will die and give you a dead-stick landing opportunity.

It is not rich enough to die at part throttle, but when going anywhere from that setting, do it gradually, not at once.

Your engine will not be damaged, except by too lean a mixture setting.

Take notice; there are two controls to idle, the idle stop screw, which should be screwed out far enough, so the throttle could be closed by the trim lever (or the radio's cut-off switch), but in enough so the throttle drum cannot fall out.

The idle mixture is the small screw inside the middle of the throttle barrel/arm. It controls the fuel curve at idle and mid-range settings.

If the idle mixture is adjusted perfectly in level flight attitude, it will become too lean and will often die, if the plane is lifted nose-up, at idle. In the air it will not happen, since the plane is slowing down, thus reducing the effort to suck fuel.