I have a 1980 444 Case that I use only for snow blowing. So it sits all summer in the garage. The tractor ran fine a couple of months ago when I fixed the snow blower. Now it will not start.I am getting gas to the carburetor, I took the fuel line off and the fuel pump squirts gas real good. My guess is the carburetor is gummed up with the chemical we buy at the gas station and put in our Gas tanks. Question is what should I soak this carburetor in to eat up the Gunk. Or have I drawn the wrong conclusion as to what is wrong with the engine. The engine is the 14 horse Kohler. Hind sight is I should have put some sea foam it the gas tank from time to time. I have used this tractor for the last 25 years or so with no problems with gas until now so I did not think it would be a problem. Guess I was wrong. Any suggestions?