Originally Posted by Ridin' Green
There is only about a 2 hp difference in those two engines when rated under the same system. I'll take a Kawi over a Kohler any day if they are both carbed.
Just remember how as of 2014 the rating system was changed..."In the past the standard permits the advertised rated value (the label on the engine) to be 85% of the test values.” For example, on an engine labeled 19 hp, the actual horsepower of the engine could be anywhere from 16 to 19 hp. Under the new revision to SAE J1940 the actual horsepower listed on the motor will be at least 95% of the actual, tested horsepower. In other words, an engine labeled as 19 hp will actually produce 18-19 hp at a certain rpm."
Even under the "old" J1940 rating standard, yes they were allowed 15% which in reality could bring the stamped Kohler 27 down into the 23 hp range legally, but that by no means proves it is only 23 hp. The 27 hp Kohler could in actuality be a 24, 25, or 26 hp engine, just because it states an allowable 15%; this does not mean that percentage is actually met.
Besides that, I've operated both carburetored engines on the same mower and the the 27 hp Kohler would out perform the Kawasaki by a considerable amount.