Small Engines (Lawn Mowers, etc.): compression testing, compression tester, compression release

Question
What isthe compression rating of a good small  B&4 or Kohler ride on lawn mower engine.
I tested a few that I was looking to buy. One had a 12.5 B&S, one had a 13 B&S , one had a 17.5 B&S and one had a 12.5 Kohler. All used ride ons.
Not one of then had a compression readinf over 60 PSI. I thought if good they should have at least 80-90 PSI. dO THEY ALL HAVE A DECOMPRSSION built in.
If yes can this be done to get a good reading. Crank it over and get 60 PSI. Remove the tester, crank it over. Put thetester back in still with the reading at 60 and crank it again.
Thank you
Roberto

Answer
 Hello Roberto:

 Even with the Compression Release the Compression I Look for is 70PSI Minimum. How do the Engines Run? If the Compression Reslease is Set Close, you May get only 60PSI. I have had this Happen a Few Times and have Found that was the Case. If your Compression Tester is like mine it will Lock at the Cylinder Pressure Regardless of where the Release is Set. Hope this Helps. Let me know what Happens, Please.