honda 13 hp engine parts | eBay www›Search›honda 13 hp engine partsFind great deals on eBay for honda 13 hp engine parts. Shop with confidence. Skip to main content. eBay Logo: 13 HP Honda Engine. 13 HP Engine. 13 HP Engine Honda GX390. 13 HP Kohler Engine. Feedback. Leave feedback about your eBay search experience - opens in new window or tab. Honda GX390 Engine Parts - Honda Lawn Mower Parts Honda GX390 13HP Engine Parts Honda GX390 13hp Engine Parts Diagrams Honda's GX390 13 HP engine is the largest single cylinder OHV engine that Honda builds. It boasts a small foot print for easy mounting and can power applications that pose difficulty in mounting a twin cylinder engine. The GX 390 is quiet, smooth and vibration free.