Best thing is to use the factory paint the dealer sells. Almost always is superior quality acrylic enamel as opposed to older, and less durable alkyd enamel. As well, the price through the dealer is usually inexpensive in that it's in the manufacturers' best interests to see their equipment looking nicely painted. Thin it all with acetone and use Rustoleum Rusty Metal primer or just regular Rustoleum primer if the metal is clean. Piece 'o cake.
Get a harbor Freight HVLP $40/$26 paint gun, some disposable paint cups and you're good to go.
Skip the hardener added to the paint unless you have a "supplied air" system or a death wish.
Also, there are a number of rebuild and/or repaint threads here. Do a search.
And, other than a learning curve, that's pretty much all there is to it.