HARRY - I'd suggest loosing the Vibra-tach and getting one of these,
http://www.extech.com/instruments/product.asp?catid=21&prodid=252
Every engine I own has had idle & max RPM set with it. I got mine thru Amazon.com, seems like I paid $40-$50 but cheaper versions can be found. If you feel lucky, Harbor Freight has a Chinese import for less than $20 sometimes. Think Donny T, Charlie, and a couple others here have them. Works on ANYTHING that rotates, just stick a little 1/8th inch square piece of reflective tape on the part that rotates, point & shoot. My only suggestion is to pull the cheap imported batteries (two AA cells) out between uses, they tend to leak & corrode.
MATT - If your mowers have to run WFO to mow properly, I'd suggest sharpening your mower blades more frequently. I typically sharpen my blades every 2-3 mowings of my 2 acres.
Wasn't it Mike Frade who posted a couple days ago that his CC runs hotter WFO mowing than at less than wide open? I remember he took infrared thermal pic's a year ago. Granted the blower incorporated into the flywheel moves maximum air flow at maximum RPM, but your not considering the extra power required to run that fast the engine has to create, therefore produces more heat. As I've said dozens of times, running WFO is a "SAFE" recommendation, meaning the engine cooling system is moving the maximum amount of cooling air for ALL engine operating conditions up to and including maximum full load. Running the engine slower reduces air flow in a direct proportion to the RPM the engine operates at. Half throttle, half the air, one-third throttle, one third the air, etc. The key is to know your equipment well enough to know how big the load is your putting on the tractor. And for those mowing with a hydro tractor, it's too easy to increase mowing speed so mowing wide open is probably best. But this summer I've used a gear drive ALL year.
At times I do run wide open when mowing, depending entirely on the conditions, taller grass equals more RPM, more HP, better mowing job for the conditions. And since I'm mowing with only a 38 inch deck this year, I ALWAYS take a full width cut, and mow in 1st gear with the 72 because 2nd gear is too fast in my situation. But where the grass is short, or sparce, there's no need for maximum RPM, so I idle down some. Back when I used to blow snow with my CC, there were places I didn't want to blow snow 20-25 ft, so I idled down there too.
The way the air cooling system on the Kohler operates, no temp. regulation, it's very easy to "Over-Cool" the engine in winter. First winter I had my freshly rebuilt K241 in the 72 I moved a lot of snow that winter. The following spring I sent an oil sample in for oil analysis. Due to all the cold operating conditions, and the fact that even cleaning 3-4 driveways every snow fall, the oil was never getting up to temp to boil/vaporize out the excess gasoline from the choking to get the engine started, and the cold running, the OA came back with DANGEROUS high dissolved gasoline levels. Some day I'll do what Dave Kirk, Mike Frade, and maybe others have done and put a tach, an oil temp, head temp, and Exh temp gauge on the 72 so I can monitor temps in relation to RPM. But I can assure you the temps will definitely be load related more so RPM related. In the mean time I'll continue to use this,
http://www.toolking.com/raytek-st25-autopro-infrared-temperature-gun?CAWELAID=844510711&cagpspn=pla&gclid=CJjtm4KDtbICFQGDnQod_UcAHg to monitor engine temps if I think something needs to be checked. I will caution people, the cheaper Raytech I had 20 yrs ago was NOT shielded well enough and didn't like checking the head temp on the K301 in my 129 one day. Cost me $50 plus shipping to CA to repair the thing I paid $70 for, but this new one has better shielding. But the "Noise" the Kohler ignition systems put out is really bad, so I don't recommend checking head or oil pan temp unless the engine is off.
