Small Engines (Lawn Mowers, etc.): Toro 2 cycle snow thrower, ca. 1968, adjustment screws, head gasket

Question
Trying to get my uncle's old Toro to start, I put in a new plug, at it starts and runs, but the motor seems to "race" and it runs excessively smokey.  The gas/oil mix he has on hand is eight years old, but originally included a fuel stabilizer.  I have tried to adjust the idle speed screws, which help some, but not too much, especially the smokiness.

Answer
First get rid of the old gas. Gas with stabilizer is good for maybe 90 days. Next to a compression test of the engine. If you do not have a compression tester gasket dealer to do it. There should be at least 90lbs per square inch. More is fine, less is not.

There is a read valve on the side of the cylinder.  You will notice a small plate with two fasteners. Remove this plate replace the two read valves on the side of the cylinder as well as a gasket be sure your exhaust ports are clean.

Gasoline mixed or not will leave a varnish deposits on everything it has touched. I would remove the tank and thoroughly clean it and replace all of the rubber lines on the machine. Next would be purchasing a carburetor kit and installing it. While the carburetor is a part be sure to clean all gas and air passages use the wire from a twister to do this. If you do not have an air compressor use a Canon of compressed air used to clean computer keyboards.

Once that is accomplished turned to adjustment screws in all the way and lightly seat them. Back to low-speed out 1 turn, and the high-speed screw 1 1/2 to 2 turns. Start the engine and adjust from that point. Do not purchase a large quantity of gas and mix it with oil. There is summer fuel and winter fuel being sold by gas stations the volatility of the winter fuel is designed to be used in cold weather summer fuel takes considerably more the to properly igniteit.  The proper mix ratio for that old of an engine would be 32:1 or 8 ounces of oil to 2 gallons of gasoline.

Another thought would be replacing the head gasket when you are replacing the reed valves. Use a wooden block clean the top of the piston and the underside of the head. This will also be an excellent time to clean the exhaust ports.

Good luck on your project