The oil tank is half full no leak while not running and sitting level.
I’m taking it out in a few days to see about the oil leak.
You just nullified finding the top cap seal as your potential problem if it's the problem. It shows up on a full tank (or near full) with the engine tilted all the way up sitting overnight or longer. First clue is you have oil in the bottom of the engine compartment when you take the cowling off and peer down at the front of the engine.
The gear is Phenolic. It's a reinforced resin material. It made up some of the components with which we were associated at work. It's akin to Matt reinforced fiberglas and is tough. Reason for using was probably because it was quieter than a metal gear to gear drive mechanism and there isn't much load (ft-lbs) on the oil pump shaft.
There are 3 bolts as I recall holding the oil pump in place. One hose and the bolts have to be removed and the pump comes out far enough to pull the drive gear with its connecting shaft out of the housing. Reconnect the hose and bolts and that's it. A word of caution, if you choose to pursue this avenue, install premix in your tank prior to undertaking.
The oil ratio of the pump output varies from about 80:1 in the idle area speeds and increases to 50:1 as the RPMs increase....per a note in the service manual.
