I have always used Champs although I have had people tell me they wouldn't give me a nickle for a truck load of them..My current tractor uses the RC12YC and even with it burning oil I haven't had any problems with them.

So far, all I can find on the 2 plugs is that # 3071 is a Platinum "Super plug" version of the standard RC12YC plug which uses Copper. Interestingly, I found the gap listed as .040" for both plugs.

I carefully checked again the gap on my Champion 3071, and it is .030 inches. After a year of use, the spark plug is in very good shape. The only reason I would stay at .030 is that it ran well and came from the factory that way. An aerodynamics expert in detonation may know something about the reason for the different gaps, but Kohler should give clear instructions to the user about the spark plug options and proper gapping which may vary by spark plug type.

I went to the Kohler web site, and they have an owner's manual, "Kohler Courage SV470-610," which gives much more detail including a discussion of the spark plug options on page 11. The gap should be .030, and the Champion 3710 and RC12YC are allowable options. It is unfortunate that the "Operator's Manual" and the "Repair Parts Manual" we get with this equipment does not include this.

For what it's worth I've always replaced the plug with what the original was and never had any problems. Most of my small engines came with Champion.

My JD tractor has a Kohler engine. The JD manual recommends one gap and Kohler recommends another. 030" vs. .040" as best I remember.

Hi,
I have a Sears tractor with a 16 HP Kohler Command Vertical crankshaft engine, CV16. It uses the Champion spark plug RC12YC, and the Kohler spark plug part number is 12 132 02-S. Unfortunately, there are conflicting data on the spark plug gap. The Sears tractor manual says 0.040" (p. 5). The freely available Kohler service manual at http://www.kohlerengines.com/onlinecatalog/pdf/tp_2339_d.pdf
says 0.030" (p. 1.10). I would suggest following the Kohler
specification.