tuning problem with O.S. .91 FX

by john zimmerman
(san antonio texas 78255)

Have three of these engines. One, after many problems, blowing glow plugs, vibrating the head loose, vibrating the prop nut off, overheating and dying while in flight, ect. began to run consistently. The other has done ok, bought it used, had been in a crash but it ran well.

The third engine won't idle well and sometimes just stops while running. I've bought a new mixture control screw and wondering how to install it. From its appearance, it must be installed from inside the carburetor opening as there are two flanges and o rings that appear larger than the outside opening for Screwdriver adjustment.