Name:   CAT BOAT - Subject:   Yamaha four stroke Date:   3/13/2017 1:57:33 PM

Thats a good question.  As a Yamaha Dealer, I can say that Yamaha Corp. is very high on maintanence and service.  Depending on the size of your YAMAHA outboard, Yamaha offers a complete oil change kit to make it easy on "do it yourselfers".  The kit comes with everything you need.  Down to the replacement oil drain screw gasket.  Oil, Filter, etc. packed in one simple kit.  IT is available at your local Yamaha dealer, and in not too expensive.  As a Yamaha dealer, I am suggesting using Yamaha products.  I have used other oils, with no appearant problems, but in no way am I suggesting you do that.  What size engine to you have?