When my Bounder broken down and I was towed to a truck/rv garage in Layfette, La. They had a nice Holiday Rambler diesel pusher there they were working on. I asked what was the problem and the owner said the owner of the rv was sick for six months, couldn't start it every month and it fouled up the injectors and they were replacing them. Could that be your problem? I've ran Cat engines all my working life and NEVER had a engine's fuel system lose prime while sitting, even over the winter. The owner of the garage said it had something to do with the fuel, the sulfur being taken out of it.