Hello,I'm new to this forum and looking for some help.We were recently given a power unit from a oliver combine and are trying to determine what model combine it came from and a approximate year.
  To start out the engine is a continental model Y91 four cylinder flat head.It has no provision for any electric starter or generator of any sort only a hand crank for starting.It uses a marvel carb and a fairbanks morse type J magneto.It has no water pump it uses a thermosiphon system to circulate the coolant.
 The fuel tank is mounted on top of the engine and is round like a barrel laid on its side,probably holds three or four gallons.It reminds me alot of the old hart parr tractor fuel tanks.
 It has a Oliver P.T.O. over center clutch mounted on the rear and drove the combine with a double roller chain.When the clutch is engaged it also pushes the trottle to operating speed and pulls the throttle to idle when its diengaged.
 After alot of tinkering and tuning we have it starting and running great.The previous owner has passed on but his family thought he removed it from the machine at least fourty years ago.But werent sure.Any help in I.D.ing which model combine this came from would be greatly appreciated.    

                                    Thanks in advance Mike