Random question about Honda gx 340 engine

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I thought I’d ask here because people seem knowledgeable and friendly but it has nothing to do with my Comanche.  
I have a generator with a Honda GX 340 motor on it. During a recent three day power outage I was using it and everything was working perfectly. Sometimes I’d shut it off using the fuel shut off valve but if I knew I was going to be starting it again soon, I would just flip the switch off. 
Once the main power came back on, I didn’t bother running it out of fuel and just shut it off. The next morning, I went out to start it up and run it dry for storage, and I noticed that fuel was dripping from the carburetor, and when I tried pull the recoil to start, it seemed frozen. With a lot of strength, I could get the engine to move but nowhere near enough. Thinking maybe for some crazy reason that it had run out of oil I pulled the dipstick and out flooded a mixture of gas and oil. I was sure it was pooched.
But, I pulled the spark plug, drained all the fluids, replaced all the fluids, let it dry out, and got it started. Lots of black smoke at first but everything seems OK now. With my rudimentary knowledge I can’t really figure out what happened and how it would go from running great to that situation overnight. I was thinking I’d at least need to clean or replace something on the carburetor but once I got it going, haven’t bothered.  Should I anyway? Should I always use the shut off valve?
Thanks folks I’m just hoping that if I can understand how it happened maybe I’ll know where to look next time.

[89 MJ]

Does it have a fuel pump or is it gravity fed? 
Some pictures of the fuel line at the carb would help determine that. I’d guess that the diaphragm on the fuel pump gave up the ghost and it pumped fuel into the crankcase. 

[FrankTheDog]

Always shut it off by turning the gas off. That way you won’t flood the engine again.

Everything l have that’s not a 2 stroke gets the gas shut off to turn it off.
I also run startron in all my occasionally run equipment. 

[vfb]

It’s gravity fed. I wondered about the diaphragm but if broke or was compromised I don’t understand how it’s working ok now. Admittedly I haven’t run it for hours but it’s been good for half an hour at least. 

[FrankTheDog]

Could be a piece of debris got caught in between the float needle and its seat.

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8 minutes ago, FrankTheDog said:

Could be a piece of debris got caught in between the float needle and its seat.

That makes sense 

[OldSch88L]

Common problem I see in my line of work, espescially when I fix the clients' stuff. I'm a mechanic at a tool rental store, so I fix anything from weedwackers to excavators. Focus on the part that says "especially on clients' stuff"... We run all our machines on super unleaded, as well as use super unleaded to make some two-stroke mix, because it's the only grade without ethanol. Most people cheap out and run their machines on plain old regular, and man, modern regular fuel is utter garbage; just bottom-of-the-dumpster juice. The junk it leaves in carburetors if you barely let it sit for a moment it beyond me. And then even with an ultrasonic clean and a rebuid kit, we still can't get them to ever run right again. Do youself a favor, and run super unleaded from now on, and put some fuel stabilizer in the tank.

[vfb]

Thanks. Lesson learned! 
I guess I’m one of those who cheaped out. Generally I run super unleaded in all my machines but with these power outages becoming longer and spending a fortune on gas to keep the generator going, I thought “well it’s supposed to run on regular so how bad can it be if it’s running steady?”  Obviously I found out 🥺

[mjeff87]

Either a stuck float or needle valve, as Frank mentions.  Might not be a bad idea to pop the fuel bowl off and clean/inspect things.

[FrankTheDog]

13 hours ago, mjeff87 said:

Either a stuck float or needle valve, as Frank mentions.  Might not be a bad idea to pop the fuel bowl off and clean/inspect things.

This, pull the carburetor off and on a clean surface disassemble it and clean it. Use carb cleaner to clean out the passages.

 

i use a small masons plastic mixing tub  I picked up at Home Depot to clean my fuel system stuff. If anything falls out it can’t go anywhere’s.

[vfb]

I appreciate the advice. I’ll take some time on the weekend for carb cleaning! 

[gogmorgo]

Anywhere that experiences vibrations can jiggle the float around enough to cause this, leaving it with the fuel turned on while it’s riding around in the back of the truck.
I wouldn’t be too concerned about ethanol in the gas. Some of us have been running ethanol fuels for decades and it doesn’t do this. It does allow for some water entrainment which can cause corrosion if you leave it sitting, but in some climates having the water stay in the fuel instead of separating out (and freezing) is a good thing. 
The biggest issue I’ve seen with generators is the tank is always full of nasty ancient gas. Seems like when the power goes out, most people top off the tank from the gas can they haven’t filled since the previous summer, then run it for a couple hours until the power comes back on. Then it sits for a month until it happens again, and they top off from the same can of old gas as last time.
My recommendation is to drain the fuel tank during your seasonal maintenance session, refill partway with fresh gas, maybe with a little seafoam or otherwise mixed in. And make sure you’re swapping the spare gas out, try for monthly. Dump it in a truck or something and refill the can. 
 

[FrankTheDog]

Startron disperses the water throughout the the fuel. I run it in everything except my daily drivers.