My father-in-law gave me his snowblower but unfortunately we can't seem to locate manual. Need to change oil and spark plug, wondering what type of stroke this model is, 2 or 4. What is the recommended oil type to use. How much oil would I pour in once oil chamber was empty. Pretty sure oil needs to be mixed in with gas as well as a regular chamber for engine oil. Any help or a manual I could print off for this model would be helpful. Thanks.