Hi Chris,   trying to get my 77 gas going after a long major overhaul.  Have just tried cranking by hand then with the starter -- leaving ignition off.  (I put a little oil in the spark plug holes.)  

Not surprising that it's stiff, new pistons, rings, bearings etc.  But the starter will not consistently turn it over.  Part of a revolution then it stalls.  If you release the starter button and push again it will go another partial turn.

My battery is old though I had it on the charger for several hours.  Also tried my neighbor's 6 v battery from his JD B, good battery but same results.

What should I try next?

Thanks very much.

Tom