PLT OF SMA HELI FORCED TO LAND OUT OF A TAXI HOVER WHEN THE ENG QUIT DUE TO FUEL EXHAUSTION.

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I'M WORKING ON AN INST RATING HELI (AS AN ADD-ON TO MY INST RATING AIRPLANE). MY HELI CFII AND I PREFLTED THE HELI BEFORE FLYING IT. WE INTENDED AN INST TRAINING FLT OF ABOUT 1.5 HRS. THE FUEL GAUGE INDICATED ABOUT A LITTLE LESS THAN 180 LBS OF FUEL. MY HELI CFII 'DIP-STICKED' THE FUEL TANKS AND DETERMINED THAT WE HAD APPROX 28 GALLONS ABOARD BEFORE FLT. WE EXPECTED TO BURN ABOUT 12.5 GALLONS OF FUEL PER FLT HR. WE TOOK OFF AND CONDUCTED INST TRAINING ON THE NDB AND ILS APCHS TO FORT COLLINS LOVELAND ARPT (FNL). I MONITORED OUR FUEL STATE DURING THE TRAINING FLT. WE DEPARTED FNL FOR OUR RETURN TO 48V AND NOTED THAT THE FUEL GAUGE INDICATED ABOUT 30-40 LBS OF FUEL REMAINING. THE FUEL GAUGE INDICATED A DROP IN OUR FUEL TO ALMOST '0' LBS WHILE WE WERE ENRTE TO 48V. AS A RESULT; WE MADE A PRECAUTIONARY LNDG AT PARKLAND ARPT -- A PVT AIRFIELD JUST A FEW MI N OF OUR DEST; 48V. WE PERSUADED A FRIENDLY RESIDENT TO TURN ON THEIR FUEL PUMP FOR US TO ADD 10-12 GALLONS OF FUEL. MY HELI CFII REFUELED THE ACFT WHILE HE; I AND THE PARKLAND ARPT RESIDENT ALL OBSERVED THE FUEL PUMP. THE FUEL PUMP GAUGE INDICATOR WAS BLACK LETTERS ON WHITE MOVING PANELS TO SHOW THE AMOUNT OF FUEL PUMPED. THERE WAS NO DECIMAL ON THE GAUGE. THERE WERE NO OBVIOUS 1/10 GALLON INDICATOR NUMERALS. THE PUMP HOSE WAS ABOUT 2 INCHES IN DIAMETER AND IN GOOD CONDITION. MY HELI CFII PUMPED 100LL FUEL INTO EACH OF THE HELI'S 2 FUEL TANKS -- INTO 1 TANK UNTIL THE FUEL PUMP INDICATOR READ '6' AND INTO THE SECOND TANK UNTIL THE FUEL PUMP INDICATOR READ '12.' WHILE PREFLTING THE HELI AGAIN; WE NOTICED THAT ITS FUEL GAUGE STILL INDICATED '0' FUEL. BECAUSE THAT GAUGE HAS HISTORICALLY INTERMITTENTLY INDICATED '0' INSTEAD OF THE ACTUAL FUEL STATE AND BECAUSE WE THOUGHT THAT WE HAD JUST ON-LOADED 12 GALLONS OF FUEL; WE DISBELIEVED THE HELI FUEL GAUGE; TOOK OFF; AND FLEW BACK TO 48V. I MADE THE APCH TO LAND AND WAS HOVER TAXIING BACK TO THE FUEL TANKS WHEN THE ENG SPUTTERED AND QUIT; REQUIRING AN UNPLANNED EMER LNDG FROM A 3 FT HOVER TAXI. THE LNDG WAS SMOOTH; RESULTING IN NO DAMAGE OR INJURY OF ANY KIND. THE FUEL TANKS WERE FOUND TO BE COMPLETELY DRY (AFTER A FLT OF ONLY A FEW (3-5) MI). POSTFLT CHKING OF THE TANKS; FUEL BOOST PUMPS AND LINES REVEALED NO LEAKS OR MALFUNCTIONS. I BELIEVE THAT WE MISREAD THE FUEL PUMP GAUGES WHEN REFUELING THE HELI AT PARKLAND ARPT. I BELIEVE THAT WE ONLY ON-LOADED 1.2 GALLONS OF FUEL (NOT 12 GALLONS AS WE HAD THOUGHT). IN ADDITION TO RELYING ON OUR MEMORY OF FILLING THE TANKS; WE SHOULD HAVE TAKEN THE TIME TO HAVE 'DIP-STICKED' THE FUEL TANKS TO BE COMPLETELY CERTAIN ABOUT THE AMOUNT OF FUEL ON-LOADED. I PAID $20.00 CASH TO THE HELPFUL PARKLAND ARPT RESIDENT THAT LET US PUMP FUEL INTO THE HELI AND THANKED HIM FOR THE '12 GALLONS OF FUEL;' IN RETROSPECT; THAT FUEL (PROBABLY ONLY 1.2 GALLONS) WAS ONE OF THE BEST BUYS THAT I'VE EVER MADE SINCE IT ALLOWED US TO FLY ALL THE WAY BACK TO 48V BEFORE THE ENG QUIT ON THE RAMP OF OUR DEST -- RATHER THAN IN THE AIR REQUIRING A 'REAL' AUTOROTATION TO THE GND WITH ITS ATTENDANT RISKS OF ACFT DAMAGE AND INJURY TO ME AND MY HELI CFII. THE ENTIRE FLT CONSISTED OF 1.8 HRS OF OP ON THE HELI'S HOBBS METER.