I had a mechanic
look at it today. He thinks he can pull the seal without removing the gear
case cover by threading screws into the seal and pulling. He thinks if this does not work he will have to pull the engine to drop the oil pan. From my read of the engine breakdown, only the front 6 bolts of the oil pan go into the gear
case cover. It looks possible to pull the cover by removing these 6 bolts and then the remainder of the bolts holding the gear case cover to the engine block.
Has anyone pulled a gear case cover from the front of the Yanmar
without dropping the oil pan?