My son-in-law recently gave me a used Snapper with a 9HP B&S engine that his brother had worked on. I used it last week with no problem. Started it this week and it started blowing oil out the air intake tube. Any suggestions as to the problem? Checked the oil before I started it and the oil level was very high on the dipstick. Inserted the dipstick and checked the oil level again, and it showed on the high end of the normal range. Checked it just now and it show on the high end of the normal range. Any thoughts?