We consider the quadratic eigenvalues problem (QEP) of gyroscopic systems (λ 2 M + λG + K)x = 0, with M = M being positive definite, G = −G , and K = K being negative semidefinite. In [1], it is shown that all eigenvalues of the QEP can be found by finding the maximal solution of a nonlinear matrix equation Z + A Z −1 A = Q under the assumption that the QEP has no eigenvalues on the imaginary axis. Although for some cases when the QEP has eigenvalues on the imaginary axis, the algorithm proposed in [1] also works, but the convergence is much slower. In this paper, we consider the general case when the QEP has eigenvalues on the imaginary axis. We propose an eigenvalue shifting technique to modify the original gyroscopic system to a new gyroscopic system, which changes the eigenvalues on the imaginary axis to eigenvalues with nonzero real parts, while keeps other eigenpairs unchanged. This ensures that the algorithm for the maximal solution of the nonlinear matrix equation converges quadratically. Numerical examples illustrate the efficiency of our method.