I'm getting my 29" 9.0 HP snowblower (model 536.887995) ready for the winter. I changed the oil and spark plug and it starts up fine, but it runs a little rough; surging constantly. I figured the carburetor probably needed cleaned so i took it off and cleaned it with some carb cleaner. I took the main jet out and cleaned the ports with a small wire. The gaskets look good and I put it back together (no parts left over!) but now i'm having trouble starting the engine. I used the prime button but it didn't sound like gas was going into the carburetor. i pushed the prime button several times and it sounded like some went in and the engine started for a second and quickly turned off. When i primed it a few times again it would start, but again only run for a second or two. Any idea what i could do to troubleshoot it?