Disagree, ask yourself one question, would you pay going market price for this machine.
And it will run just fine with not a drop of oil in it....the lifters will work just fine.
IMHO not good advice in this post at all, and I bet I have blown up more engines (Drag racing, then road racing) then any of you I would bet. You are going to destroy the cam, cam bearings, rod bearings, mains, rockers, pushrods, pistons....the list goes on and on. Think about it, how long do you think it takes to toast a bearing....a blink of an eye, I have seen pistons with no ring groves left that got shut down the sec the pressure went to nothing and the light went on. Yes it was wound a little tighter then 3k of our tractors, but the point is it takes no time at all....we will not get into the heat issue at all here.
I do agree that trading it off is bad karma, bad juju, negative vibes man....whatever. But I would be VERY leery on that motor. But I do think there are two ways to play this. Run it till it dies, or unload it. I doubt if you tell the dealer they will give you a good price on the tractor but your mind will be clear in that you did the right thing.
If you do keep it however I would change the oil at about 3-5 hours, little engines don't hold that much. I would do a pure synthetic and perhaps a tad more heavy weight oil.
Good luck to you.
My two bits, did not mean to tick anyone off with all this.
The engine didn't run without oil all the time it was draining. It likely took about a minute for all the oil to drain so some oil was still circulating until the level got too low for the sump pump to pick it up.
Surely you did some damage or at least extra wear to the engine, but if it isn't knocking or making any funny noise, I doubt that you caused damage severe enough to cause immediate or near future catastrophic failure. The rod bearings would likely be the first to go and the piston rings. Keep an eye on the oil usage and if it is not using any oil, the rings must be ok. If rod bearings, it will develop a knock and even a low sounding knock is time to shut it down and overhaul it before you throw a rod thru the block.
I don't know if your engine has hydraulic lifters but if so, they are likely the cause for shutdown due to lack of oil and perhaps they shut down prior to any major damage happening.