Procedure to operate an electromechanical level transmitter, wherein a displacer element attached to a measuring wire is lowered into a liquid in a container in such a way that, in a state of equilibrium, a resulting weight force (F res) of the displacer element is equal to a weight force (F G) of the displacer element minus a buoyancy force (F B) of the displacer element that depends on a predefined equilibrium volume (V B) when immersed into the liquid in the state of equilibrium, wherein the resulting weight force (F res) is determined and kept constant at a value by means of a corresponding variation in the length of the measuring wire, wherein the value is predefined in such a way that it is equal to a value determined using the predefined equilibrium volume (V B), said value being the value of the resulting weight force (F res) in the state of equilibrium in which the predefined equilibrium volume (V B) is immersed into the liquid, wherein the level of the liquid is determined by means of the length of the lowered measuring wire, characterized in that operation diagnosis is performed, wherein - a density (ρ liq) of the liquid and the predefined value of the equilibrium volume (V B) of the displacer element are specified as parameters for the level transmitter, - wherein, on the basis of the parameters, the level transmitter uses an evaluation algorithm to determine the resulting weight force (F res) of the displacer element in the state of equilibrium, - wherein, for the purpose of operation diagnosis, the predefined value of the equilibrium volume (V B) of the displacer element is varied with a defined change in the equilibrium volume (ΔV B) by changing the parameter of the equilibrium volume (V B) in the evaluation algorithm of the electromechanical level transmitter in such a way that either the equilibrium volume (V B) is increased up to an upper limit of the equilibrium volume (V BH), wherein the displacer element is lowered to a first height h B1 measured from the upper edge of the displacer element, or that the equilibrium volume (V B) is reduced to a lower limit of the equilibrium volume (V BL), causing the displacer element to be raised up to a second height h B2 measured from the upper edge of the displacer element, and - the resulting change in the length of the measuring wire is determined on the basis of the value depending on the value of the equilibrium volume (V B) at which the resulting weight force (F res) is maintained. - a density (ρ liq) of the liquid and the predefined value of the equilibrium volume (V B) of the displacer element are specified as parameters for the level transmitter, - wherein, on the basis of the parameters, the level transmitter uses an evaluation algorithm to determine the resulting weight force (F res) of the displacer element in the state of equilibrium, - wherein, for the purpose of operation diagnosis, the predefined value of the equilibrium volume (V B) of the displacer element is varied with a defined change in the equilibrium volume (ΔV B) by changing the parameter of the equilibrium volume (V B) in the evaluation algorithm of the electromechanical level transmitter in such a way that either the equilibrium volume (V B) is increased up to an upper limit of the equilibrium volume (V BH), wherein the displacer element is lowered to a first height h B1 measured from the upper edge of the displacer element, or that the equilibrium volume (V B) is reduced to a lower limit of the equilibrium volume (V BL), causing the displacer element to be raised up to a second height h B2 measured from the upper edge of the displacer element, and - the resulting change in the length of the measuring wire is determined on the basis of the value depending on the value of the equilibrium volume (V B) at which the resulting weight force (F res) is maintained.