ST heads can turn either direction.
Doesn't matter and nothing needs to be done, or is there a fan that needs to be reversed?
If you look into the pully end of the generator vents, you can see the fan. They are straight, aligned perpendicular to the shaft so will move the same ammount of air regardless of which way it spins. Going to make the same 4 recomendations associated with the ST series.
1. Check all the crimped connections throughly, especially down inside the main case. Pull hard on them, better they come off in your hand then when the thing is spinning.
2. Get some small expanded metal wire mesh(used for putting up stucco, available at building supply stores) and make an air vent screen for the underside of the generator casing on the driven end. I folded mine up over the ends and used the lower side vent screws to hold it in place Mice love the inside for nesting, but it makes a real mess when you spin one up with a nest inside:)
3. Replace the stock diode bridge with a more robust solid state unit. Not expensive, available at places liks surpluscenter.com.
4. IF you are going to run long hours on it, replace the bearings with better quality sealed units...