1979 4.5 hp Merc

[renoduckman]

Hi i have a 1979 4.5 hp merc that is leaking fuel and driving me crazy. In the past i have rebuilt the carb. I just replaced the fuel lines. I dont see any leaking from the pump or the lines. I can squzze the primer bulb hard enough to hurt my hand and get no leaks. But when the motor runs i seem to get alot of unburned fuel and a messy looking oil inside the cowl that runs out hole in back of bottom of cowl. The motor runs well and will troll all day long. I keep thinking i have a leak. Can this motor just be so messy and all with being old tech that its normall? Its just a 1 cyl. I keep thinking i must have a crack in the carb or what, bad gasket on motor someplace. Any one with exp with this motor or ideas on what to look at ?