Yep, the hand crank fuel pumps are a mystery. They sometimes seem completely locked up and then later in the day work perfectly. I buy at least two of them a year. I am still adding to the hangar, building ARFs, and I use the hand crank pumps to give an indication of the rate of fuel burn for new planes/engines/props.

Does anyone have experience with the electric pumps? If they are more reliable I may go that route.