Potential replacements for Onan engines include those manufactured by Kohler, Honda, Kawasaki and Vanguard, as of 2015. Alternatively, Small Engine Warehouse offers a conversion kit to update an Onan engine, which includes a new PTO belt, throttle cable and muffler.
The approximate starting prices of conversion kits and replacements for Onan engines range from about $1,500 to $1,600. Because Onan engine production ceased in 2003, Onan engine owners often experience difficulty in finding replacement parts. Compatible parts may also be difficult to find because even the latest Onan engine model lacks the new overhead valve design of modern small engines, which saves fuel, reduces harmful emissions and makes engines last longer.