AN ACR MDT WITH BALKY FUEL GAUGES GETS AN INCORRECT FUEL LOAD.

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WHILE DOING CHKLIST PRIOR TO ENG START NOTICED FUEL GAUGE ON R TANK (DIGITAL) READING 340 POUNDS. ACFT WAS FUELED TO 4200 POUNDS/2100 PER SIDE RESET CB TO NO AVAIL; CALLED MAINT. THEY REPLACED GAUGE ALSO TO NO AVAIL. AT THIS POINT I WAS TOLD THAT GAUGES (DIGITAL) WOULD BE MEL'D AND MAINT WOULD USE THE MAGNETIC INDICATORS; MAINT STICKED BOTH TANKS TO FIND THAT WE WERE SHORT 125 GALLONS ON THE R TANK. AFTER SEVERAL CHK WE CALLED FUELERS TO ADD 125 GALLONS. BOTH TANKS WERE CHKED AND BELIEVED TO HAVE EQUAL FUEL IN BOTH TANKS -- 2200 POUNDS PER TANK OR 18 INCHS ON THE STICKS. BECAUSE OF WX AT DEST ATC STOPPED ALL FLT AFTER WE HAD SAT ON TAXIWAY FOR 45 MINS. WE TAXIED BACK TO THE GATE; DEPLANED PAX; AND WERE DONE FOR THE DAY. I DID SPEAK TO THE NEXT CREW TO TAKE THE ACFT; AND EXPLAINED IN DETAIL THE PROBLEM WE HAD BECAUSE OF THE FUEL WE USED AND THE FUEL THEY NEEDED MORE THEY ALSO HAD MAINT STICK THE TANKS. THEY FOUNDED THE R TANK LOWER THAN THE L AND HAD THE FUELER BAL THE LOAD. UPON TKOF ACFT ROLLED TO THE R; CREW CORRECTED; ON CLB R DIGITAL FUEL GAUGES CORRECTED ITSELF AND READ 1100 POUNDS IMBAL. THIS CREW CONTINUED BECAUSE 1212 POUNDS IS MAX FUEL IMBAL; AND STATED THAT WHEN THEY CALLED MAINT THEY WERE TOLD TO CONTINUE THAT IT COULDN'T BE THAT FAR OUT OF BAL; THAT IT WAS THE GAUGE THAT NEEDED TO BE CALIBRATED. IT WOULD SEEM THAT THE MAGNETIC INDICATORS ON THESE ACFT ARE NOT A RELIABLE SOURCE ON INFO FOR FUEL LOADS.