Honda 5.5 LawnMower Where the heck is oil Drain Plug... The Sears people say to invert the mower draining the oil out via the fill tube...I find this difficult to believe Help Model 917.378551?

That's exactly how it's done I have the same mower. There is no drain plug on the motor, only the fill tube. Tip it on it;s side with the fuel shut off valve closed. I let mine rest on a coffee can until it quits dripping. Then put back in about 20 oz's of oil.