In this manuscript, the performance of a passively Q-switched fiber laser has been presented, where a segment of un-pumped erbium-doped fiber (EDF) is used as the saturable absorber (SA). We have taken an erbium and ytterbium (Er/Yb) co-doped double cladding fiber as the gain media for efficient pump absorption and checked the potential of the laser by changing the length of the in-house fabricated erbium-doped fiber saturable absorber (EFSA). For a fixed length of EFSA, variation of important system parameters such as output power, repetition rate, pulse width, etc, with the change of the pump power has also been reported. The laser has delivered pulses of a minimum duration of 1.35 µs with maximum energy of 2.8 µJ. The repetition rate varies in the range from 24.8 kHz to 47 kHz with alteration of the length of the SA. The central wavelength of the output spectra is 1566 nm.