Its a 1951 5HP made by OMC's Gale Products Division and private labeled for Montgomery Ward. Google OB motor manuals and several companies that offer reprints will come up.
There are plenty of reprint factory manuals right here at iboats.Just search "gale outboad manuals"
Your motor is based on the Gale 5D10 I believe it has a clutch for neutral and 360 degree reverse.