Zero mode of the Fourier series of some modular graphs from Poincare series

We consider specific linear combinations of two loop modular graph functions on the toroidal worldsheet with $2s$ links for $s=2,3$ and $4$. In each case, it satisfies an eigenvalue equation with source terms involving $E_{2s}$ and $E_s^2$ only. On removing certain combinations of $E_{2s}$ and $E_s^2$ from it, we express the resulting expression as an absolutely convergent Poincare series. This is used to calculate the power behaved terms in the asymptotic expansion of the zero mode of the Fourier expansion of these graphs in a simple manner.