21.0 Gross HP - Briggs & Stratton Model # 331877-2371 - Engine.

Every engine carries a 30-day warranty from the date of delivery against defects, unless the product listing states otherwise.

Where a listing says no manufacturer warranty applies, our 30-day warranty is the warranty that applies. Full terms are in our Terms & Conditions.

Free shipping to all 50 US states (including Alaska, Hawaii and Washington, DC). Orders are dispatched within 5 business days, and delivery usually takes 3–7 business days after dispatch. We do not ship to US territories, PO Boxes or APO/FPO addresses. See our Shipping Policy.

Free 30-day returns: return an unused, uninstalled engine in its original packaging within 30 days of delivery for a full refund. We pay the return shipping and there is no restocking fee. See our Return & Refund Policy.

Check the shaft, horsepower and model details below against your old engine before ordering. Not sure it fits? Ask us first.