Method for regulating the power delivered by a reciprocating engine, that comprises the following stages: - definition of the value of a constant time interval T1; - definition of the values of an upper threshold for the engine rpm and of an upper threshold for the percentage opening of the throttle valve of said engine; - definition of an operating area below said thresholds (101, 102) in the Cartesian graph xy whose axes represent the value of the engine rpm and of the percentage opening of said throttle valve TPS; and that comprises, during the operation of said engine, the following stages: a) measuring, for each engine cycle, the value of the engine RPM (10, 11, 12, 13) at the level of a predefined angular position (α) of the crankshaft in a specific stroke (IS, PS) of said engine cycle, said angular position (α) being constant for all the engine cycles; b) calculating, at the final instant of each time interval T1 belonging to a plurality of consecutive time intervals T1 (200, 201, 202), an activation value X* obtained from the comparison between the last RPM value measured before said final instant and the last RPM value measured before the initial instant of said time interval T1; c) verifying, at said final instant of said time interval T1, if said activation value X* differs from zero; d) if said activation value X* differs from zero, verifying, at said final instant of said time interval T1, if the last values of the engine RPM and of the percentage opening of said throttle valve TPS measured before said final instant fall within said operating area; e) if said activation value X* differs from zero and said verification carried out in stage d) gives a positive income, activating the engine power reduction by a percentage value P(X*) that is directly proportional to said activation value X*. - definition of the value of a constant time interval T1; - definition of the values of an upper threshold for the engine rpm and of an upper threshold for the percentage opening of the throttle valve of said engine; - definition of an operating area below said thresholds (101, 102) in the Cartesian graph xy whose axes represent the value of the engine rpm and of the percentage opening of said throttle valve TPS; and that comprises, during the operation of said engine, the following stages: a) measuring, for each engine cycle, the value of the engine RPM (10, 11, 12, 13) at the level of a predefined angular position (α) of the crankshaft in a specific stroke (IS, PS) of said engine cycle, said angular position (α) being constant for all the engine cycles; b) calculating, at the final instant of each time interval T1 belonging to a plurality of consecutive time intervals T1 (200, 201, 202), an activation value X* obtained from the comparison between the last RPM value measured before said final instant and the last RPM value measured before the initial instant of said time interval T1; c) verifying, at said final instant of said time interval T1, if said activation value X* differs from zero; d) if said activation value X* differs from zero, verifying, at said final instant of said time interval T1, if the last values of the engine RPM and of the percentage opening of said throttle valve TPS measured before said final instant fall within said operating area; e) if said activation value X* differs from zero and said verification carried out in stage d) gives a positive income, activating the engine power reduction by a percentage value P(X*) that is directly proportional to said activation value X*. a) measuring, for each engine cycle, the value of the engine RPM (10, 11, 12, 13) at the level of a predefined angular position (α) of the crankshaft in a specific stroke (IS, PS) of said engine cycle, said angular position (α) being constant for all the engine cycles; b) calculating, at the final instant of each time interval T1 belonging to a plurality of consecutive time intervals T1 (200, 201, 202), an activation value X* obtained from the comparison between the last RPM value measured before said final instant and the last RPM value measured before the initial instant of said time interval T1; c) verifying, at said final instant of said time interval T1, if said activation value X* differs from zero; d) if said activation value X* differs from zero, verifying, at said final instant of said time interval T1, if the last values of the engine RPM and of the percentage opening of said throttle valve TPS measured before said final instant fall within said operating area; e) if said activation value X* differs from zero and said verification carried out in stage d) gives a positive income, activating the engine power reduction by a percentage value P(X*) that is directly proportional to said activation value X*.