I have a customers Craftsman tractor, with a Tecumseh OHV17 204605B engine. Yes, I scavenged this tractor 917.252502 and put a good Tecumseh engine that I had laying around. The customer has been using this arrangement for a number of years and now the carb started running lean, he had to have almost full choke. So, he asked me to throw a carburetor on it. I am on my SECOND new carb, 640330, and both never shut off the gas, air box fills with gas. I did pinch off the fuel and got it to start on the second carburetor but it would run very rich! I made sure the choke was not engaged and I also noticed after it ran for awhile, the intake manifold was dripping water...cold as ice! Never seen anything like this! So, is anyone familiar with these Tecumseh carbs? Could I have gotten another carb that won't shut off the fuel?