How about this? I know it is the 14hp, but its the commercial model and based on the 15hp. Made from various motors past and recent. Hope this helps.
http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1988&hp=14
This one appears to have the larger gearcase from the 22CI engines…Hopefully the author of this post has ordered the correct parts book I found for him…