The article presents experimental research that has been carried out on a marine, 4-stroke, 3-cylinder, turbocharged engine. During testing, the engine operated at a constant rotational speed of 750 rpm and a load from 0 kW to 280 kW. The engine was fuelled by diesel oil of known specification and loaded by electric generator with water resistance. The fuel consumption was measured during the engine operation with fuel nozzles with different geometries. The measurement of the fuel consumption was carried out using a weighing system that was designed, constructed, and manufactured by the “KAIZEN” scientific research team at the Faculty of Mechanical Engineering at the Gdynia Maritime University. The results of measurements show changes in the fuel consumption by the engine with the geometry of the injected fuel spray. The research facility is Sulzer’s 3-cylinder, 4-stroke, turbocharged AL25/30 piston engine. The fuel system consists of Bosch injection pumps controlled by a rotation speed regulator. Fuel injectors are centrally located in the cylinder heads of the engine.