Bitter learning curve. Absolutely DONE with carburetors!!!

Well there are a few ways, mechanical pump diaphram ruptures and pumps fuel into oil. Or electric pump was on and not regulated properly and fuel blew past the needle and seat dumping down the carb past the rings. Or the float was set way to high and fuel would dribble past the boosters. The last two should have given a lot of warning before or at first start up. The last one happened to me but I cought it quickly.