I was breaking in my new DA-100 on test stand yesterday and run pretty good for 2 hours. Today I tried to run it another two hours on test stand, it start easily and run about 20 min then quit, I tried to re-start it but can't, flip it and it run about 7 or 8 sec. then stop, it can't run continuouly, I checked fuel line, there is no leakage, check spark of plug, it fire, I just can't find any error but it can't run, do know why, I am using 92 fuel with 1:32 and let engine running at 2000 rpm for breaking in. any thought about this problem, appreciate your help.