{"product_id":"engine-briggs-44s977-0032-g1","title":"Briggs \u0026 Stratton 44S977-0032-G1 Engine | 25 HP, 1-Inch Vertical Shaft","description":"\u003ch2\u003eOverview\u003c\/h2\u003e\n\u003cp\u003eRestore reliable power to your riding mower or zero-turn with the \u003cstrong\u003eBriggs \u0026amp; Stratton 44S977-0032-G1 Professional Series engine\u003c\/strong\u003e. This seller-listed new engine delivers \u003cstrong\u003e25 gross HP\u003c\/strong\u003e from a \u003cstrong\u003e724cc V-twin\u003c\/strong\u003e and features a \u003cstrong\u003e1-inch diameter × 3-5\/32-inch vertical crankshaft\u003c\/strong\u003e, electric start with ReadyStart, and a 16-amp charging system.\u003c\/p\u003e\n\u003cp\u003eThe 44S977 series is a widely used Professional Series platform for residential and light-commercial mowers. This specific 0032-G1 specification uses the common 1-inch shaft configuration that fits the majority of mid-size riding mowers and many zero-turns.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eConfirm the complete engine specification before ordering.\u003c\/strong\u003e Match the full model-type-code number and physical shaft dimensions of your original engine. The 0032 and 0033 versions of this family use different shaft diameters and are not interchangeable.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eBriggs \u0026amp; Stratton 44S977-0032-G1 Specifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e Briggs \u0026amp; Stratton\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine number:\u003c\/strong\u003e 44S977-0032-G1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSeries:\u003c\/strong\u003e Professional Series\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePower:\u003c\/strong\u003e 25 gross HP\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDisplacement:\u003c\/strong\u003e 724cc\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConfiguration:\u003c\/strong\u003e V-twin, overhead valve, vertical shaft\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrankshaft:\u003c\/strong\u003e 1-inch diameter × 3-5\/32-inch length\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eKeyway:\u003c\/strong\u003e 1\/4 inch\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrankshaft end:\u003c\/strong\u003e Drilled and tapped 7\/16-20\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStarting system:\u003c\/strong\u003e Electric start with ReadyStart\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCharging system:\u003c\/strong\u003e 16 amp\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLubrication:\u003c\/strong\u003e Full-pressure lubrication with oil filter\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCylinder construction:\u003c\/strong\u003e Dura-Bore cast iron sleeves\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMuffler:\u003c\/strong\u003e Typically not included (confirm with seller)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCondition:\u003c\/strong\u003e New, as listed by the seller\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eShaft dimensions, charging system, and included components reflect the selected seller’s advertised configuration. Compare them with your original engine and confirm the complete code of the engine supplied.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eRiding Mower and Zero-Turn Engine Fitment\u003c\/h2\u003e\n\u003cp\u003eThis listing is organized around the \u003cstrong\u003e44S977-0032-G1\u003c\/strong\u003e specification. A 25 HP Briggs Professional Series engine is a starting point for comparison, not automatic confirmation that this exact specification will fit.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine identification:\u003c\/strong\u003e Compare the full model, type, and code number stamped on your original engine.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrankshaft:\u003c\/strong\u003e Confirm 1-inch diameter, usable length, keyway, and retaining-bolt thread. This is not a substitute for a 1-1\/8-inch shaft application.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMounting and clearance:\u003c\/strong\u003e Check mounting pattern, engine height, and clearance around the air cleaner, oil filter, and exhaust.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePTO clutch and drive pulley:\u003c\/strong\u003e Confirm shaft engagement, pulley position, and belt alignment. A 1-1\/8-inch clutch bore will not fit this shaft.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eElectrical system:\u003c\/strong\u003e Match starter connections, charging requirements, and safety-circuit wiring.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eControls:\u003c\/strong\u003e Confirm how the mower’s throttle and choke (or ReadyStart) arrangement works with this engine.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eCommon cross-references include earlier 44S877 and 44Q777 Professional Series engines with the 1-inch shaft. Always confirm the exact original specification with the seller before ordering.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eWhat’s Included?\u003c\/h2\u003e\n\u003cp\u003eOne engine in the seller’s advertised 44S977-0032-G1 configuration. Confirm whether a muffler, wiring harness, or installation hardware is included, and which components must be transferred from your existing engine.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eBuy Through the Selected eBay Seller\u003c\/h2\u003e\n\u003cp\u003eUse the button to view the seller’s current price, stock, shipping options, and purchase terms. Payment, fulfillment, returns, and any warranty arrangements are handled through the seller’s offer. Price and availability may change.\u003c\/p\u003e\n\u003chr\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003ch3\u003eIs 44S977-0032-G1 the same as 44S977-0033-G1?\u003c\/h3\u003e\n\u003cp\u003eNo. The \u003cstrong\u003e0032\u003c\/strong\u003e version uses a \u003cstrong\u003e1-inch × 3-5\/32-inch shaft\u003c\/strong\u003e. The \u003cstrong\u003e0033\u003c\/strong\u003e version uses a \u003cstrong\u003e1-1\/8-inch × 4-19\/64-inch shaft\u003c\/strong\u003e. That difference affects the PTO clutch, drive pulley, and installation.\u003c\/p\u003e\n\u003ch3\u003eCan I select this engine by horsepower alone?\u003c\/h3\u003e\n\u003cp\u003eNo. Use the original engine’s complete model and type number first. Horsepower, mower brand, and deck size alone do not establish compatibility.\u003c\/p\u003e\n\u003ch3\u003eCan I reuse my existing PTO clutch?\u003c\/h3\u003e\n\u003cp\u003eOnly if its bore, mounting arrangement, and position match the 1-inch replacement shaft and your mower’s drive system.\u003c\/p\u003e\n\u003chr\u003e\n\u003cp\u003eNeed help identifying your existing engine? \u003ca href=\"\/pages\/contact\"\u003e\u003cstrong\u003eContact PTO Direct USA\u003c\/strong\u003e\u003c\/a\u003e with clear photos of the engine model\/type\/code label and your mower identification tag.\u003c\/p\u003e\n\u003cp\u003eCompare other options in our \u003ca href=\"\/collections\/engines\"\u003e\u003cstrong\u003ereplacement engine collection\u003c\/strong\u003e\u003c\/a\u003e, or browse our \u003ca href=\"\/collections\/pto-clutches\"\u003e\u003cstrong\u003eelectric PTO clutch catalog\u003c\/strong\u003e\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003e\u003csmall\u003e\u003cstrong\u003eAffiliate disclosure:\u003c\/strong\u003e PTO Direct USA may earn a commission from qualifying purchases made through links on this page.\u003c\/small\u003e\u003c\/p\u003e","brand":"Briggs \u0026 Stratton","offers":[{"title":"Default Title","offer_id":67987064357231,"sku":"ENGINE-44S977-0032-G1","price":1211.97,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0957\/5058\/6735\/files\/engine-44S977-0032-g1.jpg?v=1793591767","url":"https:\/\/ptodirectusa.com\/products\/engine-briggs-44s977-0032-g1","provider":"PTO Direct USA","version":"1.0","type":"link"}