Hung, my math was wrong. A 150 has 22.5 usable and a 152 has 24.5. It’s 1 gallon per side so 2 gallons total. So at 6 gallons per hour fuel burned would mean 20 minutes
But in the Club Newsletter with the article about fuel sticks (attached in the other thread from John), at the end of Page 7 it said "What about using a 152 FuelHawk tube on a Cessna 150? Ironically, the 152 FuelHawk is more precise on a 150 than it is on a 152", along with a table of data to back up that statement. So, one could use the 152 Fuel Hawk stick on a 150 with fairly accurate results.