OK, here are some more pictures of the crankcase drain passages on Charlie’s engine:
OK, it is hard to see, but the groove in the crankcase does extend into the groove where the oring was…Hard to see, but the little vacuum port is in that groove where the oring was…In my feeble mind, I’m thinking that oring does not belong there. Having the oring in the groove kinda plugs up the vacuum port and system efficiency. So, to me, having the oring in place was either a manufacturing or engineering oversight, I don’t think this powerhead has ever been apart before. I’m guessing this engine is in such nice shape cuz it was rarely used due to the constant oil fouling of the mag plate…
What do you guys think? I wish that this crazy system was used in conjunction with the conventional oring sealing. In other words leave the crankcase groove above the conventional oring groove, along with the vacuum port. They could have even added another circular groove around the upper bearing as well…