Small Engines (Lawn Mowers, etc.): adding hour/tach meter, huricane season, plug fire

Question
hi , i am build a 10 k generator for this huricane season. for power i have a b&s 18 hp twin II model 422707  .  i want to add a tach/ hour meter( kind that reads off the field of the plug wire). my question is per engine revolution how many times will one plug fire (wasted spark?).  also what is the factory iddle rpm and high rpm set at on this motor.  thanks, sven of sarasota

Answer
 Hello Sven:

 The Idle Varies Due to a Lot of Engine Variables. 800 to 1200 RPM's Depending on Load at Idle. The High Is 3200 RPS's. Red Line is 3800 RPM's. These Figures will you within a Range that will Allow the Engine to Perform at Its Maxium Effeciency. The Spark Plugs Fire Only when they Are Supposed to Fire. There is No Wasted Spark. Hope this Helps. Let me know what Happens, Please.

 Good Luck

 Respectfully

 John