Fuel consumption can vary by as much as 2 X depending upon needle setting.

I have a Saito 91 and the flight timer has been set to 20 minutes forever. Recently a premature dead stick occurred and small amount of trash was found in the fuel inlet. Several months later the airplane was flown again and it was obvious by the smoke that I forgot to set the needle after flushing the carb. The engine had plenty of power and ran OK. I ran out of fuel at 11 minutes.

Bill