ORIGINAL: causeitflies
Flames can also be caused by too much gas or liquid getting into the engine.
Usually big yellow (low temp) flames out the back won't hurt the engine because the flames are out in the air and not inside. However they can cause problems to the airframe if not confined to the pipe. Long blue flames mean high temps inside the engine.
Good, I should have mentioned the flame I got was a yellowish redish diffuse flame, Only lasted about 5 seconds.
Now you said "too much gas or liquid" in the engine. Im assuming you mean starting gas in the liquid form. Could an incodent with JUST starting gas be dangerous?
Pete