Small Engines (Lawn Mowers, etc.): Kohler CV15S-41526 ACR Problem, explosive hydrogen gas, gasoline vapors

Question
I have 10 plus yr old Craftsman rider with a Kohler Command CV15s-41526 engine.  The tractor model is 917.256552 and the serial no. is 0620096C012601.

I am having trouble with the starter not being able to turn over the engine because it seems to be in compression.  I can manually release the compression by turning the flywheel.  However this is a major pain in the butt and it blows gas out the exhaust when I do get it started.  

At first this happened only once in a while but now it is every time.  

I consider myself a fairly competent mechanic and I am wondering if I can "fix" this ACR problem.  Not much info available out there.

Thanks,
Bill White

Answer
Bill
First make sure that the battery is fully charged,this will cause a engine not to crank.
A 12 volt battery with a minimum current rating of 250
cold cranking amps is recommended. The requirement
depends on engine size, applications and starting
temperatures. Cranking requirements increase as
temperatures decrease and at the same time battery
capacity shrinks.
WARNING: Explosive Gases!
Batteries produce explosive hydrogen gas while being
charged.
Before disconnecting the negative (-) ground cable,
make sure all switches are OFF. If ON, a spark will
occur at the ground cable terminal which could cause
an explosion if hydrogen gas or gasoline vapors are
present.

The ACR mechanism consist of a flyweight, spring and
pivoting control pin assembly attached to the gear on
the camshaft. At cranking speeds (700 RPM or lower),
the control pin protrudes above the exhaust cam lobe.
This pushes the exhaust valve off its seat during the
first part of the compression stroke. The reduced
compression results in an effective compression ratio
of about 2:1 during cranking.

After starting, engine speed increases to over 700
RPM, and centrifugal force overcomes the force of the
flyweight spring. The flyweight moves outward, pulling
the arm of the control pin, so it pivots into the ‘‘run’’
position. The control pin no longer has any effect on
the exhaust valve and the engine operates at full
power.