In the engine manual for my Briggs and Stratton 850 I/C it says that it takes 10W30 synthetic oil. I have found it hard to find this spec except for Penrite synthetic fortified 10W30 (i.e. not a true synthetic) which specifically says it is not friction modified. The B&S manual doesn't say antything about friction modified.
I have found full synthetic Amsoil in a 10W30 but it doesn't say whether it is suitable for B&S engines, although it is very good oil. I can't see any reason why it isn't suitable but of course I am keen to know for sure given I have a four year warranty to keep current. I am also keen to avoid the standard monograde mower engine oils which are mineral based and in my experience prone to sludging.
Anyone have an answer or know of a full synthetic 10W30 approved by B&S?
