My experience is most of these pumps take somewhere in the 5 amp range. It is an electric motor and they have a higher in-rush current at startup and depending upon how fast your breaker is, it can trip. I would recommend a 10 amp breaker and appropriate wiring for these pumps. Running a breker that close to expected current is a potential problem.
N64LR - RV-6A / IO-320, Flying as of 8/2015
N11LR - RV-10, Flying as of 12/2019