441677 issue turning over

I have a 441677 engine twin that wont turn over past compression stroke, I have adjusted the valves 4 times and it does slightly get better. I messaged BS to see if this engine had a compression release and I was told "all BS engines have some kind of compression release" so fearing the worse I pulled the engine and pulled the sump cover, took out push rods and then pulled the cam... there is no compression release on this cam meaning it was not installed on this cam at the factory, so I look for a small bump somewhere on the lobes, nothing. The cam look fine the tappets look good the pushrods are not bent and valves seem fine.
I am doing a complete rebuild including rings which the cylinder still had cross hatches and appeared to be no wear other then on the piston at the bottom jacket which I believe is normal wear, I am at a loss here only thing I can think is the battery was shot and I was trying to turn it over with a 200amp charger, maybe it needs a battery with higher CCA then the charger puts out ? any ideas
Thanks
Jeff

Well that engine has a camshaft with a lobe profile which holds the Intake Valve slightly open well into the compression stroke. Either the camshaft is worn out or more likely you need to be using a different source to jump from like your car or truck and there is always the possibility someone over heated the starter causing it to lose torque.

Walt Conner