A draft beer faucet being "hard to pull" or "sticky" usually indicates a cleaning issue. Either cleaning has not being done with a chemical specifically designed for draft beer cleaning, and/or the faucet is not being disassembled and thoroughly cleaned.
To clean:
-
Pump water mixed with a cleaning chemical into the beer hose and let it soak for the time prescribed by the chemical manufacturer.
-
Then, thoroughly flush the beer hose with water to remove all traces of the cleaning chemical.
-
The last and most often overlooked step is to soak the keg coupler and faucet in water with cleaning chemical then brush them clean with a cleaning brush. Rinse them completely clean with water.