Do you ever do any of your own repairs? The reason I ask is that some times with a little coaching you may be able to fix the hose leak yourself. Is this like a van cut away ford or gm? I know shop rates are expensive, but I have been in the business and the overhead with insurance, building lease ect. special tools, and online shop manuals is a killer. I don't have a cutaway van but plenty of others here do. Same with your onan. Tell us what it is doing or not doing. Who wants to help?