Every engine gets condensation when it sits. Only way to get rid of it is to run it long enough to burn it all out of the engine when you do start it. (10 or 15 minutes should do it) Starting it to load or unload then shutting it off right away only compounds the problem--might want to consider a winch on the trailer and pull it on, push it off. When you do your runs, make sure you warm the engine up sufficiently before you make your pass, especially now when we're getting into cooler temps. I use one of the little hand held pyrometers with the laser pointer to make sure the engine is up to temp before a pass....