hey tknobby you might be right also about the crankcase vent tubing length having to do with humidity being able to enter the crankcase. if the volume of air being exchanged back and forth from the crankcase is less than the volume of the hose then the outside air will not enter the case.this is with the engine running of course and plugging the line might help when sitting idle. if this makes no sense i might be able to reword it.

Gary