Prop pitch for 1995 15 hp Johnson

[Mike Redmond]

I,ve recently purchased a 1995 15hp Johnson regular leg manual start,,the prop that is on it looks bad,found a used replacement for it wich was what was on it in the first place a 9 1/2X10.. the salesman proposed me a 9X11 what is the general difference between the two ,,,how would it affect my motor I am pushing different boats with it, form a 350 lbs jonboat to 200lbs skiffs,,,dimention wise they are quite close performance wise???