I know a guy named Rob in New York has put one on his machine. He agrees it's heavy, but is satisfied with it. BUT, he hasn't figured out how to attach an OPC yet. Diesel engines typically come with a kill switch that is always off unless you pull out a lever. The OPCs on walk-behinds are always on, unless you hold down a lever. The Lombardinis Joel puts on the machines all need to have a plate changed so that he can have an OPC. It's a fairly simple task with the Loms, dunno about the yanmar clones. You can surely run without an OPC, but sure is nice to know that the machine will stop when you let go.