MER in Seattle does classes for Yanmar engines and probably John Deere too, if you can find several others to do the class with you. These folks have the chops. They service fishing boat fleets up and down the west coast. I just did a class for 4JH series diesels and it was well worth the money and time. Kind of funny, 5 of us sailboat guys looking at the this puny little sailboat diesel while all around us were these behemoth 6 cylinder jobs. They covered cooling, battery and charging, valve adjust, injector removal and testing, impeller replacement and any questions we had. Time well spent. Their classes are not well publicized, I never would have know of them had I not stopped in to buy some Yanmar parts and chat a bit with them. Stevie is in charge of classes.