Original owner probably use the Tamiya connector as Battery. The igniter should have banana plugs. Female banana plugs should be installed on the backing of starter box for easy plug-in. Does it look like BigDog's Post?? If banana male & female plug are missing, can purchase in Radio Shack of maybe your LHS.

12v 7a battery. Battery use on a Uninterupted Power Supply(UPS). Car battery to heavy to transport. UpS battery is only 6". Like a motorcycle battery. And alot cheaper. 7mah to 9mah are available.