Briggs and Stratton 15.5 narrows it down to about 250 variations. The reason I asked for the model number was to determine if this is L head, OHV, Opposed twin, V twin, because they all have different approaches to repair. I L head, or Opposed twin the model number will be on the blower housing either over the spark plug, or could be a a tag next to the flywheel The OHv engines will be stamped into a valve cover.