Best size for my '80 Johnson 70 HP Seahorse

[Searun1]

I have been having a hard time getting an answer on this one. Does anyone have an early '80's or similar 70 HP Johnson prop recomendation? I have two props that came with the boat. Sorry for my ignorance but can't tell you what size they are. I have them at the shop right now and they will tell me when my boats turn comes up...<br /><br />Anyways the engine seems to be maxed out a little low right now (again don't know exact RPM's as there is no tach, I'm working on that as we speak.) <br /><br />What would be the ideal size for this engine on a 16' mid size glass runabout?<br /><br />Thanks for the help guys...<br /><br />Searun1

 

[ob]

Re: Best size for my '80 Johnson 70 HP Seahorse

You'll likely end up with either a 13 3/8 X 17 or a 13 1/2 X 15 prop ,depending on which one will allow your engine to run at or near 6000 rpm with a light load.This is assuming that the engine is mounted at its optimal height on transom.Good luck.