Generally , if its got fuel leaking from the prop drive , its looseing fuel , and the consuptions higher , flights shorter . AND its messy . Which is whay a sealed bearings pretty much a standard fit these days . Pe Oil ! .
You dont want a dry seal in anything . Particularly water pumps - You drop anti freeze on the seal & spin . Try something similar - See its lubed - as theres less circulation up there with it atmospherically sealed .