Running rough fleetwood cornado

RVs are notorious for dried up gas clogging everything. Especially if yours is a carburetor or throttle body engine...fuel injectors are also subject to gumming up. I suspect a thorough cleaning of the entire fuel system will be required. There are getting to be so few mechanics capable of carburetor rebuilding, replacement's usually in order. If you've ever taken anything apart that has dried gas in it, it becomes obvious that no chemical will completely dissolve those deposits. Mechanical cleaning (or boiling in a hot tank) is necessary. Seafoam helps keep deposits at bay but something really gummed up won't benefit from it.