Going to try and give back to this forum. I was in exactly the same place with a 17hp Kawasaki yesterday. I purchased a new plug, as was recommended, flushed the tank because I did have old fuel. Unlike you. Removed and cleaned the carburetor. Removed the float valve and seat and the little tube above the seat. Ran a small wire or drill bit in every hole and flushed with cleaner. There are three very small holes inside by the butterfly that are hard to see. Reassembled and it fired with cleaner. Not recommending this, it is just what I did. It ran on the cleaner for a few seconds and then ran on gas and is doing fine. Hope this helps.