Yanmar Experience ?

[quartersplash]

I have replaced the front main oil seal on my Yanmar 3JH 2CE engine twice because there was oil slinging all over the engine compartment in line with crankshaft pulley.
I finally got someone small enough to crawl over the engine to get a good look at where the leak was, and discovered a small hole just to the left of the crank pulley in the gear case. Maybe slightly smaller than a pencil eraser head. I took a look at the other engine and no such hole. Anybody ever hear of this problem before or have experience with it? Since I only have a hole in the one engine, I am assuming that it is not some kind of breather hole....
Thanks

[Chief Engineer]

Post a picture if you are able too.