If you know that the engine is going to sit idle for several months then a small shot of oil in it will keep the inner workings from rusting. After run oil, Marvels Mystery oil, or even automatic transmission fliud will do the trick. Remove the glow plug and put a small squirt in the cylinder and another small squirt in the carb, then turn the engine over by hand a few times to work the oil in. Replace the glow plug and you'll be good.

Ken