Re: Montgomery Ward outboard
You need to look again. That is an invalid number. I see a GG-8971A, which is a 1957 12hp, and a GG-18741A, which is a 1961 25hp Electric start.
Anyway, all Sea Kings with GG in the model number were made by Gale Products Division of Outboard Marine Corporation (OMC). Depending on model, it may be similar to Evinrude and Johnson motors. But some models are very different.
Look at the serial number. There will be two numbers, followed by an "X". Reverse those two numbers and you have the year. 85X is 1958, 36X is 1963, etc.