Petrol King Fuel pressure Regulator (8mm Tails). The Petrol King Fuel pressure Regulator is suitable fo most Fuels except Methanol. Fuel pressure Adjustment may be set up to any Fuel pressure Range between 1 to 7 psi. Regulates the pulsation of the Fuel Pump Prevents Overflowing of caburetter Improve the performance of the engine Enables Fuel savings from 5 - 10%.