Originally posted by DennyW
No damage Matt. It all depends on how accurate you want the check, and at the same cranking rpm's. A no load test will keep rpm's closer because by the time you get to the last depending on battery condition, you may be 75 rpm's slower.
Proping the throttle open is so no fuel is sucked down the intake into the cylinders. Again, depends on how close you want the test, and you want a clear air flow to the cylinders also.
I will have to check it again the way you said. I had 1 and 3 cylenders odd from the rest, they were low but within 10%, 1 was oily and wet, 3 looked great, all the rest were just wet.