If the Carb orifice jets are clogged (there are 16 very small holes in the jet) it is almost impossible for any carb cleaner to completely clean them out. Yes, there are NO parts available for Onan carbs in the past 20 years due to CAB restrictions. BUT, you can take them apart and remove the jet and manually clean out the orifice holes. It is rare for you to destroy the gasket or seals in the carb. You may have to cut the plastic cover plug adjuster off the bottom bowl adjuster to unscrew the carb fuel bowl. You can clean the jet without removing the complete carb. Once the bowl is removed you unscrew the jet from the carb. Doug