AMSOIL - Been using it for over 20 years in boats, Harleys, tractors, generators, handhelds, mowers with cheap Briggs, and all of my autos. 1986 Ford Diesel - over 286,000 miles (most of it pulling a gooseneck when I was farming) and only replaced the injection pump @126,000 and one rocker arm that apparently had a soft spot @ 200,000 miles. It was still running and not burning oil when I sold it. 1989 Dodge Cummins diesel that had 89,000 on it when I purchased, and then switched it over to Amsoil (and their Dual-remote Oil filter system) and sold it to a young rodeo fella when it had over 389,000 miles on it (half of them pulling a goose-neck horse trailer). I only replaced the turbo on this truck at around 300,000 miles, with no other type of internal engine repairs or oil consumption. A 1973 Boston Whaler with a 1982 70 hp Johnson (bought used in 1996) that I ran at least twice weekly for four years, and then sold and was still easy to start and ran like a dream. My current boat, which is a 2000 Pathfinder 1810 with a Yamaha 150 VMAX (2-cycle),has been ran on Amsoil since after the break in period. On two cycles, you will immediately notice a tremendous reduction in smoke. They also sell a waterproof grease that is great on your boat trailer bearings and is the only grease that I use anymore for anything. In the above mentioned road vehicles I would change the filter only at 5000 miles and then change the oil at 10,000 miles. Google their website (www.amsoil.com
) and check out all of their products, including their outstanding filters. Lots of stuff these days isn't anything more than "snake oil", but Amsoil products work like no other that I have personally tried. You can become an Authorized Independent Dealer for a $25.00/year fee and purchase directly from the factory with quite a savings. It costs more than conventional on a per unit basis, but I'm convinced it saves a person considerably both monetarily (in repairs & time lost) and with headaches in the long run. And no, I don't make money selling this stuff (I've been an Independent Dealer since I discovered their products), but I do sell a lot of it to my friends at my delivered cost. I will be changing over to Amsoil in my new Bad Boy ZTR after break in.