Dear All,

I am currently flying a Phoenix Topstar 60 without cowl on a OS75AX 2 stroke. As per the design of this plane, the engine is mounted inverted.

In the recent, I have had a lot of issues with tuning the engine. It either cuts in hower or in straight and level at 50%. We have tried manuplating both the needle as well as the low end screw to no avail.

Someone of the field mentioned that 2-strokes are difficult to tune inverted. Is this the case? Should I mount the engine at 90 deg? (will have to modify the firewall for the same)

Ameyam