Diesel was put into a gasoline 4010 mule then drivin. What’s the best way to drain and flush diesel out of the system?

Not familiar to your set up but as with any system encluding motor cycle. Get a hose and syphone all that you can out and fill with the proper gas. Start it up...it might be a little harder to start but once you get it started it will clear. I once had a guy fill my car with diesel...supposedly gas and I drove the car a long way then kept stopping up with gas. worked fine....sure did clean the engine.

Do what was mentioned above and also replace the fuel filter after cleaning the tank. Depending on the model, you may need to replace fuel injectors and sensors in the fuel system if they were damaged. I would also recommend disconnecting the fuel line at the engine and purging any contaminated fuel prior to trying to run the engine. Start by emptying and cleaning the tank and work your way to the engine from there.

Metopes the tank, clean tank, add clean fuel into system, then do it again.

Diesel fuel doesn't need assistance to ignite, and it has a thicker consistency than gasoline. ... You need to fix the problem immediately, as the longer diesel sits, the more damage it can do to the fuel system, engine and injectors. Next, use a siphon pump to remove the diesel from the tank and fill it up with gasoline.