I'm looking for Castrol 30W oil and cannot find it anywhere, on-line or locally. I've checked AutoZone, Advance, O'Reilly, Walmart, Lowe's and Home Depot. So I decided to try for other brands, brands I recognize, not this cheap unknown stuff. The only straight 30W I can find is Super Tech but I have seen the independent wear test run on it and is ABSOLUTELY NOT as good as the nationally-recognized name brands.
Amsoil makes a 5W-30 and 10W-30 small engine oil specifically designed for small 4-stroke power equipment including mowers. This is what the spec says for both:
Use 5W-30 Synthetic Small-Engine Oil in small engines found in (not limited to) snowblowers, generators, power washers and other equipment that requires SAE 30 or 5W-30 motor oil, including those made by Briggs & Stratton,* Honda,* Kohler,* Champion,* Generac,* Toro,* Ariens,* Troy Bilt,* John Deere,* MTD* and Husqvarna.
Use 10W-30 Synthetic Small-Engine Oil in small engines found in (not limited to) mowers (zero-turn, riding, stand-on, push), generators, power washers and other equipment that requires SAE 30 or 10W-30 motor oil, including those made by Briggs & Stratton, Honda, Kubota,* Kawasaki,* Kohler, Tecumseh,* Robin,* Onan,* Wisconsin,* Powertrain,* Yanmar,* Linamar* and Vanguard.*
So I just want to say that you should NOT be using a car oil for your mower. Two reasons.
1. Automobile engines are water-cooled. Mowers are air-cooled and get a lot hotter. The addidtives in small engine oils are designed to counter these high temps.
2. Car oils have no zinc because zinc will contaminate the catalytic converter. But, you need the protection of zinc in a small engine due to the higher compression (serves as a cushion against metal-to-metal wear).
I do not care if you use Amsoil or not - there are other small engine oils out there, but be smart about what you put in your $20,000 machine!