that depends on a lot of things, boat its on, weight load, uses, etc..., do you mean you d like to know the prop that came stock on the motor, it will be in your manual, along with the others that will work
We don't have a lot to go on but we'll assume you have a Hydrasports boat. A lot will depend on which one. It'll also depend on your application, needs & requirements for the type boating you do.
It's a 1986 Hydra-Sports TS196. My biggest problem is my holeshot. It's slow to go. The prop has marking NK26 and NN61H Precision prop. 200 HP Evinrude on a 19.5 Pro Bass hull.