help with pickin out a new prop

[treeman]

ok then I have a 1978 115 hp evinrude mod#115899c.My? is what size and pitch should i go with.and how do you read what your prop say,s on it.I mean there is alot of # on there. for instance here is the # off of my volvo penta. can you make heads or tails out of these. 441 182 21
71 14 850 864 07 126x 71 340 5 my best guess would be 14x21 but i know nothing lol.