bobodu wrote:And you didn't get the API code....just a generic graph from Amsoil...
And Briggs never recommends using a 15 weight at all. Let alone a 40 weight.
But Briggs does sells SAE 5w30 100% Synthetic oil that private labelled. Don't buy it for my customers as I can they same grade locally at a better price.

Matt wrote:rotella 15w40 for at least 25 years. in all my equipment, atv's/motorcycles...etc.
Rotella T 15W40 API Specs>
API CJ-4, CI-4 PLUS, CI-4, CH-4, CF, SM, SL, SJ, SH; ACEA E9, E7; JASO DH-2, MA; Caterpillar ECF-1A, ECF-2, ECF-3; Cummins CES 20081; DDC 93K218;
Deutz DQC III-05; MACK EO-O Premium Plus; Ford WSS-M2C171-E; MAN 3275; MB Approval 228.31; MTU Category 2; Renault Trucks RLD-3; Volvo VDS-4
The highlighted API codes are for automobile engines which the Briggs 4 cycle are in. The SH is an obsolete class but still useable. Any oil labeled that isn't rated above SE should not use any gasoline engine made after 1979.
The suffixes (0, 5, 10, 15 and 25) after the SAE followed by the letter W designate the engine oil's "winter" grade. The number after the W is the summer grade rating, no W no winter rating. As for the temperature bands for the viscosity you need take in the engine operating temperature too. Just because it is 90 outside doesn't mean the oil temperature is 90. By the time oil reaches the engine operating temperature it can be a thinner than water that why here in the South we run SAE30 in non-oil pump engines in the summer months.
I help maintained a fleet of 50 Macks and Ford Dump trucks and all we ever ran was straight SAE30 weight diesel rated engine oil. It was a bear to crank them on some of the cold mornings but they ran 9-10 hours a day without ever shutting down during the day.