Small Engines (Lawn Mowers, etc.): Finding top dead center, sears craftsman, leak down tester

Question
Eric,
I have a Kohler command CV-730 twin cylinder OHV 25 HP engine on a sears craftsman mower. My manual says that "some of the engines are equipped with Automatic Compression Relief mechanisms making an accurate compression reading difficult to obtain". Does this engine have an ACR?
If so my manual suggests using a cylinder leakdown tester. Since I know nothing about using a leak down tester I need youe advice on what is the best, easiest way to 1. find TDC in each cylinder before performing the leak down test, 2 What , in your opinion is the best way to hold the engine in this position while I perform the leakdown test, and 3. How much PSI should I apply to the cylinder?
4. Also do you have a favorite (affordable = less than $100) leak down tester you might recommend?

Best Regards,
Dave


Answer
Your engine does have a compression release...almost all do.  I typically use the Briggs leak down tester but there are many manufactures now sell them.  

To find TDC, remove the spark plug and valve cover.  Rotate the engine by hand watching the strokes. After the exhaust valve closes the intake should start to open.  Follow the intake until the valve closes.  Now use a straw inserted through the spark plug hole and continue to rotate the engine until as the piston pushes the straw to the highest point.  This should be TDC on the compression stroke.  You can use a large 1/2 inch drive socket and breaker bar to hold either the flywheel nut or crakshaft bolt.  You will have to hold the breaker bar while performing the leak down test.

Set the leak down tester to 80-90 PSI and measure the leakage.  30% or more indicates a problem.

Is the engine not starting or does it lack power?
Let me know.
Eric