Gas in oil of pony motor on RGN? How is this happening?

Might check the overflow charcoal canaster. As you go down the road the fuel will slosh and run out the vent into the canaster and then into the air cleaner housing and THEN into the carb down Into the engine.

That’s what happened to my generator. I pulled the overflow hose out of the charcoal canaster and no more problems.

 

If this is truely a gasoline eng honda, does it have a gas return line that returns a small amount of gas to the tank while it is running to keep the gas (in the engine's mechanical fuel pump) from getting too hot and boiling and causing vapor lock like many cars had near the end of when they had carbs. It could be feeding back from it especially if the tank gets hot and builds excess pressure due to a not properly pressure relieving gas cap. They are typically a pres/vacuum relieving gas cap that lets air in the tank as fuel is used. Maybe a improper aftermarket (or unvented) gas cap that isn't relieving pres. Sometimes this excess tank pres. can overcome a manual gas shut-off valve and or the carb float valve. Or the manual shut off valve is leaking slowly.

 

Stuck float in the carb, or leaking fuel pump, if it has one. Other than mistaking the oil fill for the fuel fill, that is the only way for fuel to get in the oil.
Shut the fuel off after each use. That will keep this from happening again.

 

If the problem persists after all else fails I had a Kohler pony motor on an older Trail King that after being rebuilt by a Kohler Repair dealer it was doing exact same thing. They had installed the new piston and rings with the top ring upside down. It would fill the oil completely full of gas while running. Even on a new engine this could possibly happen. I don't know how a person could tell but I would be talking with the dealer if you have tried every thing else.

 

How long are you leaving the valve open before you start it? Wondering if the float is stuck and its trickling in before you start it?

 

Sounds to me like your fuel shut off valve has become a fuel almost shut off valve, and over time the bowl fills, and naturally the bouncing around while going down the road causes fuel to leak into the cylinder, past the rings, and into the crank. Your needle/seat/float works properly though, because you haven't indicated pony run issues...
Pull the bowl, by removing the center bolt, and see if there is any trickle of fuel while in the OFF position.

 

Whatever the issue, I for one sure want to hear the final diagnosis of this issue.
I'm a gearhead, so there's nothing that peeves me more than someone who lists an endless breakdown of issues, then NEVER posts the result/reason...
Wait, maybe I'm a a Curious George?

If you were closer, I'd rip that motor out, tear it apart, and figure this out before would be able to go to sleep.