This walk-behind lawn mower from Sears features a 6.5 HP engine and large rear wheels. Here are some maintenance-related details from the Owner's Manual...

GASOLINE: Use regular unleaded, holds up to 1.6 quarts (almost 1.5L). OIL: Use SAE 30 at above-freezing temperatures, or SAE 5W-30 when it is colder than 32F. Holds up to 20 ounces.
SPARK PLUG GAP: .030 inch

Regarding the Craftsman 917.378450 lawn mower's performance and design...

PROS: Self-propelled, cuts fairly tall grass, can be serviced at Sears, many useful adjustments
CONS: Relatively heavy, has required several repairs in nine years