If the motor is not very old, you might try your local dealer, but any graphic shop would be able to make them for you. I use FastSigns for my stuff, just make sure that you ask for marine grade vinyl.
I searched everywhere online and could not find anything, but I do know of one person that may be able to help you, They sell alot of decals on ebay, you might email them and ask them.<br /><br />www.bigcityimages.com