My nephew put motor in my lawn mower instead of gas...........?

turn it over and drain the tank.................put gas into it and it should be fine............... it wont burn very clean for the first tank or 2 but it will burn it off........

Try to pump out as much of the oil out as you can. Then fill it up with fresh gasoline. It is going to smoke a lot but should eventually run fine.

Empty the gas tank. Put in some new gas and also dump that out. Replace the spark plug and you should be alright.

get as much of the motor oil out as possible, and drain the gas too, then fill the tank with premium gas and run it. The high octane should be able to run with the left over oil in there.

the tank must be cleaned of oil, and then put gas in and let it set for a day so the oil that's left can be diluted. then run it without a load on the motor for 15 minutes. will smoke for a while.

yu have to clean out oil just open a head on top of piston clean out oil then put it back toghter carefully make sure when yu open it and close it otherwise yu will make abig mass after yu dun put ges and start the mover it will takea wile to start but it will work

Buy a new mower!

thumbs down to everyone except stevetower your only other option is to remove the gas tank and fill it half way slosh it around and dump repeat again reattach the tank replace the fuel filter and spark plug and pull the rope and pray! it will smoke but should run for you. if not you will need to clean the carburetor out as well .