Re: 1986 evanrude 15Hp. impeller replacement
To take the lower unit off,remove the 6 mounting screws and take out the lower shift connecter screw ,which will only be seen after all mounting screws are removed and the lower unit drops less than an inch,leaving an access opening for removal of the shift screw. Dont try to force the lower unit apart more than the inch,it wont drop entirely until the shift screw is removed.
Are you putting in the impeller or the whole kit?