I just used car wash soap and water, a rag and a long bore brush..... Simple Green would probably work well, though.

You do have to take care it doesn't rust. I sprayed the decks and bores with WD-40 while it was still wet, blew it dry with compressed air, then sprayed the areas to be painted with brake parts cleaner before painting it.

The white color is an old habit for marine engines in dark engine spaces. The white color makes it easy to see oil leaks...... so, I thought I'd try it on this one. I doubt it'll stay very white once it's on the road, but it might be helpful initially.

Frank