My murry riding lawn mower will not start and we have changed the battery but still can not figure it out

Can you give more info on what its doing or not doing? Does it crank? Do you have spark at the plug? Anything else its doing or not doing would be helpful

Check That The Battery Is Hooked Up Correctly, Check The Fuse, Make Sure The Clutch/brake Is Fully Depressed, Check Solenoid By Taking A Piece Of Wire And Jumping From One Large Post To The Other, Check The Ground From Battery, Could Be A Bad Ground At Solenoid, Turn Key To Start Position And Take A Jumper Cable And Touch Where The Red Cable Hooks Up To The Starter, If The Starter Doesn't Turn The Engine This Way, Then Place Hands On Top Of Engine And Rotate Counter Clockwise, Then Try Again.
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Did you try the solenoid?