It's also a good idea to use a prop with a relatively high inertial mass until you've run several gallons through the engine.

APC props are good for this. They are much denser than a wooden prop or something like an Master Airscrew prop.

The additional mass helps keep the engine running when it is struggling during breakin and it helps maintain a lower idle speed.

Insanemoondoggie:

Been there... richen the low speed still more, even if it seems like you cannot get a low idle... then try flying the plane... but be prepared to land hot.

If this cures the in-air transition problem ( I bet it will! ) then you may want to use my "fix" for the low idle speed setting.

On similiar behaving SuperTigres I've taken to adjusting the LS richer then making a small half moon shaped cutout at the point of lowest throttle barrel closure. A small round file works fine for this, though you'll temporarily have to remove the throttle barrel to make the cutout.

This extends the LS range slightly while making it a bit leaner... I posted pictures of this on another thread.

The slightly enlarged opening permits you to close the throttle even more, while maintaining a leaner LS mix in spite of the richer LS needle setting.

It cured my transition problems on all similiarly aflicted ST 75 and 91 engines.... though not ALL ST's I have seem to have this problem.