A fuel system comprising: a fuel tank configured to store fuel, a pressure of the fuel within the fuel tank is equal to a first fuel pressure; an internal combustion engine fluidly connected to the fuel tank, the internal combustion engine being configured to consume fuel at a second fuel pressure lower than the first fuel pressure; a fuel regulator fluidly connecting the fuel tank to the internal combustion engine, the fuel regulator being configured to reduce the pressure of the fuel from the first fuel pressure to the second fuel pressure; an air supply assembly configured to supply air from an air inlet to the engine, the air assembly comprising: a first air supply line fluidly connecting the air inlet and the internal combustion engine; a second air supply line fluidly connecting the air inlet and the internal combustion engine, the second air supply line being in parallel with the first air supply line; and an air valve configured to adjust the air flowing through at least one of the first air supply line and the second air supply line; characterized in that: the internal combustion engine is located gravitationally above the fuel regulator; and by the first air supply line being in thermal communication with the fuel regulator. a fuel tank configured to store fuel, a pressure of the fuel within the fuel tank is equal to a first fuel pressure; an internal combustion engine fluidly connected to the fuel tank, the internal combustion engine being configured to consume fuel at a second fuel pressure lower than the first fuel pressure; a fuel regulator fluidly connecting the fuel tank to the internal combustion engine, the fuel regulator being configured to reduce the pressure of the fuel from the first fuel pressure to the second fuel pressure; an air supply assembly configured to supply air from an air inlet to the engine, the air assembly comprising: a first air supply line fluidly connecting the air inlet and the internal combustion engine; a second air supply line fluidly connecting the air inlet and the internal combustion engine, the second air supply line being in parallel with the first air supply line; and an air valve configured to adjust the air flowing through at least one of the first air supply line and the second air supply line; characterized in that: the internal combustion engine is located gravitationally above the fuel regulator; and by the first air supply line being in thermal communication with the fuel regulator. a first air supply line fluidly connecting the air inlet and the internal combustion engine; a second air supply line fluidly connecting the air inlet and the internal combustion engine, the second air supply line being in parallel with the first air supply line; and an air valve configured to adjust the air flowing through at least one of the first air supply line and the second air supply line; characterized in that: the internal combustion engine is located gravitationally above the fuel regulator; and by the first air supply line being in thermal communication with the fuel regulator. the internal combustion engine is located gravitationally above the fuel regulator; and by the first air supply line being in thermal communication with the fuel regulator.