How many of you use a straight 30wt oil for you walk behind? When I first bought my Lawnboy Platinum 10765 (Briggs 6.75 quantum engine) I ran the oil it came with for the first 5 hrs or so with no problems. I then used amsoil synthitic 5w30 / 30wt small engine oil. It didnt take long and every time I started it I would get lots of smoke upon start up. I verified correct oil level. After a month of that I returned to Briggs and stratton 30wt oil. It took alittle time but the smoking went away. A couple seasons later (now) I decided to do a mid season oil change and used synthitic Pennzoil Ultra 10w30 (used in my cars) with no problems. The engine manual and the mower manual says you can use a 5w30, 10w30 or 30wt (regular or synthetic). I figured since moving from WI to GA the added protection would be a bonus with the summer heat and thick bermuda grass. Plus the Pennzoil Ultra is actually cheaper per ounce than the Briggs oil. So what gives with the smoking before? Who else here uses multi weight "automobile" oil?