UPDATE:
I removed all the old gasket silicone, retorque to correct specs the stator cover seal, sealed all the rubber grommets with silicone. Made a test and so far the seal is NOT leaking. That is good news.
Late I re-examined the cables and just as Awk said, the source might be water entering thru the cables on the carb side, I suspect water was running down the cables. In response to that, I carefully injected silicone into the cover of the cables on the carb side, providing a good seal, later I put electric tape to protect it and on top of that, injected dielectric grease inside and covered the cables, and finished it with another layer of dielectric grease.
I have not tested it yet, but I'm confident it is completely sealed. Thanks everyone for the suggestions.