Small Engines (Lawn Mowers, etc.): Compression?, compression gauge, hp kohler

Question
Hello,
I checked my compression on a Wheel Horse Electro 12 w/ a 12 hp Kohler. The compression gauge read 40psi. I then checked my compression on a Sears Suburban Super 12 (mod. 917.25510) and it read 75. Can you tell me what the compression should be for both engines.
Thank You,
Andy

Answer
Hello Andy:

The Minimum Compression is 80psi. Usually Anything Below 80psi will Cause Erratic Idle and Other Engine Operating Problems. Depending on the Model, you May have the Engine with the Compression Release. This will Account for the Low Compression Reading. On the Most of the Engines Produced After 1988 the Compression is Checked with a Gauge Only when a Shorter Set of Valves are Installed in the Engine so the Tappets Do Not Touch or Open the Valves. The OEMs Say to Quickly Turn the Engine in Reverse Rotation and if the Engine Kicks back Sharply, then the Compression is Good. I Usually Check the Compression Both Ways. I Use the Reverse Rotation Method and the Gauge Method. I have a Shop so having a Set of Valves Ground Short for Different Engines is Not an Issue for Me. For the Sears Mower, Go to this Site Addy, http://www3.sears.com/ and Enter the Model Numbers in the Upper Left Search Box and Click Go. Then Visually Verify the Equipment and Click Continue. From this Page you can View Diagrams or Parts Lists for you Equipment. For the Kohler Engine, You can View a Breakdown of the Engine at this Site Addy; http://www.kohlerplus.com/login.asp and Select Enter as Guest. Now Select the Thumbnail of the Catalog to Wish to View. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. Have a Happy Holiday Season and May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.

Respectfully

John