This problem is not consistant and some installations will not be affected by the inverted position. We have played around with lower gas pressure and that solved the problem. Obviously, air blower also resolved the problem. The strange thing is that the same engine mounted in exact inverted position behaves differently in different airframes. We have no problem with the engine inverted in F4 and L-39 but get hung start in the Gripen. If you experience this hung start problem, please let us know.

Thank you.
Kraivuth S.