Gas leaking into engine while it's off

[1979BumbleBee]

I just bought a boat off Craigslist and the owner told me that in order to turn it off, I have to unplug the gas line from the engine and let the gas empty from the carborator, then shut it off. And to turn it on, I have to replicate the gas line in and prime the line then turn it on. If I don't do this, the engine floods and each cylinder has to be cleaned out. Can someone help me find a way to fix this? Thanks

 

[F_R]

Either the float valve in the carburetor is not seating tightly, or the fuel pump diaphragm has a pin hole through it. Fix whichever is the case. You can test the fuel pump diaphragm by removing the pump from the motor (leave hoses attached) and give the primer bulb a squeeze. Gas should not squirt out the back of the pump. It he pump has a pulse hose instead of being directly connected to the powerhead, same thing applies except remove the pulse hose instead of the pump.

 

[scout-j-m]

Do you use a portable tank or a built in tank? If it's a portable tank and you don't leave the vent open, the tank will swell with the heat and the pressure will force fuel through the fuel line if it is connected to the motor. It can overcome the needle seat in the carb and force fuel up through the carb into the throat (along with out the front and vent hole) and that can be enough to flood it upon startup. However, if you unplug the fuel line from the motor you don't necessarily have to run the fuel out of the carb. The fuel in the bowl is at atmospheric pressure because it is vented and it won't trap vapors and force fuel out. Likewise, if your fuel tank is out of the weather you can leave the vent open on it and leave it plugged in and you won't have a problem either.

 

[oldboat1]

Lot's of folks run the fuel out, attempting to help keep the carb free of varnish. It's also basic procedure to prime the carb with the hand pump before starting. Maybe you misunderstood what the PO was telling you(?) (If new to outboards, you may be flooding the motor due to a misunderstanding or two.)

What motor do you have? Got a model number?