Well Im no "expert" but I had some not so good experience with
a 40LA that was on a students Tower trainer. We fought an excessively
rich low end problem for a long time. Once you got it started and
cleaned out and in the air it was fine. But it would start to load up
as soon as you went back to idle and we had far too many flameouts
and deadstick landings. Not exactly what you want for training flights.

The LA engines have air bleed carbs. Meaning you open up the
bleed hole to allow more air in to lean the idle mixture.

First make sure the air bleed hole isnt obstructed. Then set
the air bleed adjustment screw so its half way across the bleed hole.
Start from that point.

If you cant get it lean enough even with the bleed hole fully open
(like we had with the 40LA) remove the air bleed screw entirely.
It will be able to suck additional air through the vacated adjustment
screw hole. This is the only way we got that 40LA to run right.

Mike Hammer