Whether it's a push mower or a tractor, a Poulan lawnmower needs an adequate oil supply in its engine for proper lubrication. The oil tank is separate from the gas tank, so it needs to be checked and topped off every time like the gas. If not properly lubricated, the engine will heat up and the piston will seize up.
For normal, warm weather operation above 32 F, use a standard SAE 30 weight oil. For colder temperatures, below 32 F, use SAE 5W-30 oil. These oils should be of high quality and meet the certification standards of the American Petroleum Institute. Don't use reconditioned or old automotive oil, as this can damage the engine. Keep a bottle of the recommended oil ready for each use, because if the engine's not properly lubricated, it will get ruined.
Checking Oil Level
Before starting the mower each time, check the level of oil in the oil tank. If your lawnmower is new, it wasn't shipped with oil, so it must be added. Place the lawnmower on a level, flat area to get an accurate reading of the oil. Pull the oil dipstick out of the oil spout, on the side of the engine, near the oil fill plug. Wipe the dipstick off with a rag or paper towel and stick it back into the oil spout. Pull it out again and check the reading. Oil should be located in between the measured area.
Adding More Oil
If the oil is low, you must top it off before you begin operation. Operating the lawnmower with low oil will give unsatisfactory results and may damage the engine. Open the oil fill spout and the bottle of recommended oil. Pour the oil in slowly, adding about 4 to 6 oz. at a time; use a small funnel if necessary. Check the oil level again. Add more until the level reaches in between the measured area. Clean up any spilled oil around the engine with a rag.
Changing the Oil
Poulan lawnmowers need an oil change after every 50 hours of operation or at least once a year. Change the oil when the engine is still warm, as the oil will flow more freely and remove more impurities; don't, however, change the oil when the engine is still hot. Allow the oil to cool down for at least 10 minutes. Always unhook the spark plug's boot and remove the spark plug before changing the oil. Put the lawnmower on a level surface and remove the drain plug from the bottom of the mower. Allow all of the oil to flow out into the pan. Replace the drain plug securely and add oil until the level meets the necessary amount.