what spark plug to use

[KVANDY12]

I bought a B/S motor off E-Bay. Man said it came off a sovereign tractor. 16HP no ID on motor sheet metal. Has a Starter Generator. My Briggs book say CJ-8 J-8 champion A-7nx A-71 Auto lite CS-45 GC-46 A.C. Do all these plug fit B/S motor regardles of HP? Is there any way of telling what this motor is without the motor ID tag from the motor? Ken

[RayS]

The model number, type and code should be stamped into the flywheel shroud towards the bottom on the carburator side of the engine. You could also remove the cylinder head and measure the diameter of the bore. I think the diameter on a 16hp is 3 9/16 inches. The front PTO cover on a 10 and 16 hp should be flat, at least any that I have ever seen were. Ray