yup, i'm pretty sure it's always been plain ol' magnesium... if you are going to paint the engine, may i suggest powdercoating. last summer, i painted the generator stand with clear coat hi-temp paint, but it's gone a little yellow. not sure if colour would do the same, and i have heard those arguments pauly is talking about with heat transfer/cooling; but if you're going to do it, might as well do it right.... but if you're set on doing it yourself, i found hi-temp paint does an awesome job on tin.