I have a Craftsman riding mower (42"). It has a 15 hp Kohler engine. It had set up for a while before I got it. I have put a kit in the carburetor, a new solendid valve below the carburetor bowl. I have run a small wire through the bottom where the solendid goes to make sure the jet is clear. The oil level is OK. I put in a new spark plug. The seat switch seems to be working. I crank the engine and about 3 seconds of running it shuts down, just like I turned the key off. Does anyone have a suggestion?

Just so you will know I got my lawn mower running. I soaked the carburetor in Gunk overnight and blew it out with compressed air. It runs fine now.