I bought a 1984 35 HP 2 cyl Mercury. The prop is frozen on the shaft and I expect to wreck it getting it off. I can find no numbers on it except "13" which I suspect is the pitch. Mercury shows 6 props for this motor with part numbers 48-731XXXXX pitch 10" to 17". For a 14 FT. boat I think a middle of the road 13 pitch will be fine. In looking on ebay, I find 13 spline props in the 10 to 11 inch dia. 13" pitch but the number don't match my list Whats the deal on these, will only the parts mercury list for this motor fit?