I bought a 7 hp h70 tecumseh snowblower engine but its not working. I cleaned the carb completly (even the small holes in the "screw") and turned the needle valve with the opened end toward the air intake. The guy that sold it to me said that he putted a new carb kit in it but that 1 seal was missing but I cant see wich one. I checked the compression by putting my finger in the sparkplug hole and turning the shaft and it popped off so I think its good. I checked for the spark too and it seemed ok. The oil level is good and the gas is new. The guy that sold it to me changed the fuel and prime lines on it. The motor dont want to start. The only I got it to start was by putting gas by the sparkplug before starting it and at full throttle, the motor was almost not turning, puffing like : puff puff puff puff pop puff... , the carb is leaking and its smoking white smoke a lot.