Oil tank overflow tube leaking

Both of my rotaxes drip some oil from the tube. Kitfox is on the engine mount way up inside where the factory put it, probably 6 inches above the belly. The Remos  is on the firewall 2 inches inside the cowl . I did put a bottle on it to catch it and only amounts to a spoon full over several hours. They both seem to level out at the bottom of the   flat part of the oil stick and I also fill it half way. If i fill it over half it just blows it out? 

Hi All

Please refer to the installation manuals.  The clamp band is the item to note.  This should be inline with the centre of the prop shaft to no more than 400mm below that point,.  Clearly there are a number of aircraft that have them mounted higher and these typically are what have problems with oil levels and oil migration when the engines sit for a period of time.  High oil tank position leads to a situation where there is a certain head pressure when it is not in use.  The oil then leaks slowly via the oil pump clearances back past the oil pump drive pin and camshaft clearance and into the crankcase.  Some will leak faster than others due to many factors.  Download a copy of the IM for your engine type and check it against the Rotax data.  it may be you need to spend a longer time turning the engine to return oil after sitting on your aircraft type.  

Cheers