I have a 1977 Johnson 70 HP motor & am going to change to a stainless steel prop but do not know my existing prop sie. The only numbers I find stamped on it are 508C and 139. Don't know if anyone can help with this but would appreciare it.
There should be some numbers near the hub. You may have to remove the nut to see them. <br /><br />Does this prop put you in the correct top rpm range with an average load?
