We had a 4-71 out of a Northwest Crane that was converted to be used as a PTO unit to run a Jaw crusher. Set that up with 12 volt electrical system. Last I knew it had set unused in a heated store room for 5 or more years. At that time it fired right up despite not having been run or the 4D battery charged for years.It can get to be hard to say with that old stuff is the starter marked 24v or how are you sure its 24 and are things working now ? A 4-53 isnt hard to crank and really wouldnt need 24v