Small Engines (Lawn Mowers, etc.): yard machine lawn mower, compression release, exact condition

Question
I have a 17 horse techmsuh on a yard machine lawn mower that when i turn the key over and go to start it. It will only turn over to the start of compression then it gets real slow and finishes turning over (about like a car on a dead batt. but it's a brand new batt and have it charged)

Answer
Mike,

You have not told me if the engine is an OHV   (Overhead Valve)  if it is, you need to have the valves adjusted/looked at.  There are two other problems that could cause this a partially sheared timing key, or a bad camshaft.  The compression release could be broken on the camshaft. The compression release allows the exhaust valve to partially open during starting to prevent the exact condition you are describing.

The valve clearance is the quickest and easiest to check. You may find you have a broken valve spring or valve keeper.  

Happy tinkering,

Dave