Yes there ARE small cylindrical electric
fuel pumps on boats...sometimes. If you put your hand on the cylinder and then work the switch on and off, you will feel vibration IF that switch coontrols the
pump. Sometimes such
pumps are used to help in bleeding...other times they are used as a lift assist
pump when tanks are lower than the engine. Helps in rough seas.
Caveat...there must be a filter in
line between the tank and such a
pump or you risk clogging the
fuel line at the
pump in rough weather. Carry a spare if that is indeed what you have. Any standard gas/diesel compatible 12V
pump will do and you can get them pretty cheap at any Napa store.