Narrative:

The flight was planned for 30-60 mins to perform in-flight engine tests and tuning. Departed home field with 12.5 gallons in left tank and 10 gallons in right tank. While I was focused on engine tuning; the engine lost power and stopped. I immediately turned towards ZZZ; established best glide; and contacted approach control. Approximately 1/2 way to ZZZ; I diverted to ZZZ1 because I wasn't completely sure I had enough altitude to glide to ZZZ. The landing at ZZZ1 was uneventful. After landing I discovered that during the in-flight tuning I had run the engine very rich and had used fuel at a much higher rate and had exhausted all fuel in the left tank. Engine out cause: fuel exhaustion in one tank and failure to switch tanks. I was too focused on tuning the engine and lost track of time and fuel management. During the incident; I also failed to troubleshoot -- first checking fuel and/or switching tanks. I was too focused on plting the aircraft to a safe landing and had convinced myself that I had made an error during tuning that I wouldn't be able to fix while in-flight. Callback conversation with reporter revealed the following information: the reporter stated the following: he did not declare an emergency because he was about 7 mi from the airport at 7500 ft and within easy gliding range.

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Original NASA ASRS Text

Title: THE CO-Z MK-IV PLT CONDUCTING A TEST FLT EXHAUSTED FUEL IN 1 TANK AND FAILED TO SWITCH TANKS BECAUSE HE THOUGHT THE ENG FAILURE WAS MECHANICAL.

Narrative: THE FLT WAS PLANNED FOR 30-60 MINS TO PERFORM INFLT ENG TESTS AND TUNING. DEPARTED HOME FIELD WITH 12.5 GALLONS IN L TANK AND 10 GALLONS IN R TANK. WHILE I WAS FOCUSED ON ENG TUNING; THE ENG LOST PWR AND STOPPED. I IMMEDIATELY TURNED TOWARDS ZZZ; ESTABLISHED BEST GLIDE; AND CONTACTED APCH CTL. APPROX 1/2 WAY TO ZZZ; I DIVERTED TO ZZZ1 BECAUSE I WASN'T COMPLETELY SURE I HAD ENOUGH ALT TO GLIDE TO ZZZ. THE LNDG AT ZZZ1 WAS UNEVENTFUL. AFTER LNDG I DISCOVERED THAT DURING THE INFLT TUNING I HAD RUN THE ENG VERY RICH AND HAD USED FUEL AT A MUCH HIGHER RATE AND HAD EXHAUSTED ALL FUEL IN THE L TANK. ENG OUT CAUSE: FUEL EXHAUSTION IN ONE TANK AND FAILURE TO SWITCH TANKS. I WAS TOO FOCUSED ON TUNING THE ENG AND LOST TRACK OF TIME AND FUEL MGMNT. DURING THE INCIDENT; I ALSO FAILED TO TROUBLESHOOT -- FIRST CHKING FUEL AND/OR SWITCHING TANKS. I WAS TOO FOCUSED ON PLTING THE ACFT TO A SAFE LNDG AND HAD CONVINCED MYSELF THAT I HAD MADE AN ERROR DURING TUNING THAT I WOULDN'T BE ABLE TO FIX WHILE INFLT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE FOLLOWING: HE DID NOT DECLARE AN EMER BECAUSE HE WAS ABOUT 7 MI FROM THE ARPT AT 7500 FT AND WITHIN EASY GLIDING RANGE.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.