It could be the adapter. It could be the pan gasket. I've seen more than a few pan bolts work loose. Those engines were designed to operatre at low RPM's. I always put studs in mine & nylock nuts.

Warped adapter?

Could be- could be just a loose bolt. It never ceases to amaze me the things I see- no loctite, no lock washers, no torque-wrench use. I hate bolts- studs and nuts are so much more reliable. Everywhere. They make gasket positioning not only easier but more solid and they're great assembly aids.

I figured I would update the "freaky" oil leak from my oil filter. Took my mechanic for a spin a couple weeks ago, and it turns out oil was being flung from the harmonic balancer under higher RPMs. Pulled the motor out last week, and the seal was completely shot. Getting a bottom end rebuild to match the Starboard side done last year. Should be back on the water later this week....hopefully.