Winco LLC5000H, low output

[Mad_Labs]

Howdy Folks,

Off grid and in a cloudy/rainy spell. Of course, that's when I discover the output voltage of my generator is low! I'm getting 115 and 230V and it drops as low as 90VAC under any sort of load. The generator is a Winco LLC5000H. Engine speed is not too low and load is not too great. The trouble shooting guide in the owners manual says the diode, the field coil or the stator. Any ideas which is most likely? I'm trying to determine a course of action, if it is the stator, probably too expensive to fix. Field coil maybe and diode, sure no problem.

Thanks!