Thanks to everyone who responded with suggestions and resources. For closure and post-op follow-up, I concluded that the carb jets were probably irreparably fouled with varnish and made an appointment at Best RV in Denver, an authorized Onan repair center, for professional diagnosis and repair. The cost was $500+ for new carb and installation. They did not remove the genset from the RV.
I am thinking about installing a see-through in-line fuel filter right before the carb so that when I put the RV in storage, I can measure some Sta-Bil or SeaFoam into the fuel line, run the genset a little, and watch the stabilizer flow into the carb.
Does that, and exercizing the genset monthly, sound like a good idea?
Thanks.
