The fact that you can get it to start with starter fluid sprayed in the carb throttle tells you that you have spark and sufficient compression. That leaves fuel supply as the remaining culprit. With an engine that has sat this long, you will be best off purchasing a carburetor re-build kit. They come with replacement gaskets, needle and float, etc. Also use good carb. cleaner to spray through the jets and down the throttle. If it is a B & S engine, there should be model number and type stamped into the metal shroud that covers the engine. Bring the model and type to a B & S dealer and they can get you the new kit. You may also need to clean out the tank. If there has been fuel in the tank that long it may be basically turpentine by now.