My tractor is an 04. The tachometer shows 20 but means 20 x 100 revolutions per minute. There is an index to show 540 rpm per minute at engine speed of 2300 rpm. So the engine is not getting up to the speed it needs to get to for the pto to turn at 540 rpm's. I did not have this problem before using the tiller. I am going to go check something on the tractor.