Having two 3GM30's, I can do this in my sleep. The West Marine
vacuum changer is a great piece of gear
and takes most
of the hassle out of it. Just have your engine
warmed up well before. I don't understand why they mounted the filters horizontally, since you just can't get them off neatly. I use puppy training pads underneath and that does "pretty" well, but every now and then I make a mess.
recommends 15-40 for these engines, diesel
formula, of course. Personally, I use Delo.
They're good little engines.