Which American is credited with inventing the first automobile fuel pump?

In 1885 Sylvanus Bowser patented a kerosene pump to reduce the mess of transferring kerosene from the store to a portable container. The pump used a hose and manual suction. Bowser adapted his idea to gasoline once the auto started to gain in popularity. Gas pumps still use the pump technology that Bowser created, though now it is automated rather than manual. Gas pumps used to be called bowsers in the US but the name fell out of use. However, they still call gas pumps Bowsers in both Australia and New Zealand!

https://en.wikipedia.org/wiki/Sylvanus_Bowser

The term "bowser" is alive and well in the US. A fuel bowser is a tank to dispose of reclaimed fuel. After serving in the Air Force, it was common to see a bowser on the flightline during maintenance on the fuel systems or engine. Automotive garages would also have a bowser.

https://media.defense.gov/2010/Mar/18/2000384383/2000/2000/0/100312-F-5278P-004.JPG