A parametric study on some combustion characteristics was carried out in a natural gas fueled dual plugs SI engine. Mass fraction burned, cylinder pressure histories and combustion durations of the engine were investigated by three equivalence ratio and spark advance for three spark plug configurations. It was found that equivalence ratio and spark plug configurations were more effective parameters on the total combustion duration than spark timing and was concluded that centrally located single plug configuration for equivalence ratio of 1.0 gives best combustion characteristics in compared to the other conditions. In addition, presented study showed that dual plugs serve an alternative for fast combustion in case of geometric constraints to use central location of the plug. (C) 2017 Elsevier Ltd. All rights reserved.