Volvo BB115 - Oil Leak

[MBYD]

I'm afraid I have a big problem with my engine. The engine is a 1976 Volvo BB115 (same engine as AQ130, I'm told). I have milky oil dripping from the bell housing. When I first launched and ran the boat it was dripping, but not milky and assumed it was coming from a bad main seal. The next time I ran the boat the dripping oil was milky color. The oil on the dipstick is clear. With a mirror I looked under the engine and see milky oil spurting out out from between the oil pan and the engine then running off the bell housing. I have now run the engine a couple hours and the problem persists and the dipstick is still clean. What's is it? Should I be worried? Thanks.