Start-up with the nitro spark-ignition system.  It only has a glow plug.  Simply pull the glow plug out of the engine and power it up with a glow igniter; it should glow a bright white/orange.  If it doesn’t glow at all, the cause of your problem is revealed; if it lights up poorly or the elements is white or black, the glow plug may have seen better days, and it may be time to replace it.  Spend a few buck on a new plugs; its a cheap price to pay to  save yourself the aggravation of trying to start an engine whose plug is in poor condition.