Back to the question of whether the governor shaft is vulnerable to slipping back into the crankcase. That is, if one decides to follow Taryl & Doublewide's advice to insert a seal into the shaft recess in order to stop oil from seeping out. Well, the answer seems to be "no." Something causes it to catch before it goes all the way through. Plus, if it went past that "catch" it would likely hit the side of the case thereby also stopping its travel. I happened across a GCV190 with a busted top half (cylinder) but a good bottom end. When I split the case, I went ahead & tested to see if the shaft could be pushed into the case. Below is a picture if how far it went into the case before it stopped & could go no further. The other picture (blurry) shows the tip of the shaft from the outside. Moreover, the shaft is metal; thus, I was able to pull it back into its proper place with the little magnet shown lying on the shop towel. Otherwise, it was not reachable with pliers.