Denny,
It sounds like your operating conditions should keep moisture out of the crankcase. And your top end looks like new- nice condition. Have you done dry and wet compression checks? Since water is a product of gasoline combustion, it might be reasonable to associate a higher level of crankcase moisture with compression ring leakage and blow-by. If that is the case, engine temperature and operating conditions would have a lessor effect on the crankcase humidity level. I think the blow-by idea is somewhat of a stretch, but worth investigating. In engines I've seen with worn rings and a large amount of blow-by, there typically has been a visibly larger amount of exhaust from the road draft tube. If dry and wet compression tests and/or a cylinder leakage test don't indicate ring wear, the foam might be more weather related than an engine condition, especially if cool temperatures and high humidity are prevalent.
Harvester
