There's a thread going about a Super Tigre G2300 that only likes one prop. When the owner switches to a smaller prop the engine runs for a while then quits. I have no idea if the small prop could be the problem but I'd definitely try to get one that's in the recommended range and try it.

From http://www2.towerhobbies.com/cgi-bin...?&I=LXDXM5&P=0
Suggested Prop:
Sport 16x10
Racing 16x8
Scale 18x5, 18x6