Thanks to all who answered my post of 30 july. Upon further investigation I found outthat yes there was fuel in the oil and was causing it to come out through the vent hose to the carbuerator, about four 3 lb. coffe cans full. I have also heard that besides blow-by, the float could be stuck or the diaphram on the fuel pump could have a hole in it. I will take it to a pro<br />to find out. Thanks Again...........<br /><br />I have a 1977 starcraft capri with a 140 HP Mercruiser I/O. For some reason the engine oil is coming up through the vent hose in the valve cover and into the carbuerator. Needless to say, it doesn't run well on oil. Any ideas what may be wrong. there is no water in the oil and was hoping that ruled out a cracked block. Any help, anyone can give me would be greatly appreciated. 