Just to confirm..isn't XD-25 Johnson oil the older XD30? A few told me yes; however..the 30 is red. I just ask because I always used oil from my local dealer. They now only have 30 and 50. Walmart has the 25 at 19.83 verses 28.95 on XD-30.
what are you running it in? if it's the 150hp in your signature, TCW-3 outboard motor oil is what you should be running. walmart has it, by the gallon.
From Evinrude's website, XD-100 is synthetic, XD-50 is synthetic blend. Synthetic is not mentioned in the description of XD-30, your guess is good as mine. XD-25 is not mentioned at all, must be a discontinued product.