Add to Favorite Sellers. 25 GHP Vertical Shaft Engine. Engine, 25 Gross Hp. The item “Briggs & Stratton 44S977-0033-G1 25 GHP Vertical Shaft Engine” is in sale since Monday, January 14, 2019. This item is in the category “Home & Garden\Yard, Garden & Outdoor Living\Lawn Mowers\Lawn Mower Parts & Accessories”. The seller is “outdoor_power_direct” and is located in Columbus, Ohio. This item can be shipped to United States.