I have an Onan GenSet 4000 in my 1994 Itasca that stopped working on my trip to North Dakota(purchased the RV just for that occasion).... model 4BGEFA26100K. It was running and just stopped. I checked for spark (which was good), breakers and fuses (good), and pulled the fuel filter (I think is OK) but noticed no fuel coming from the fuel pump. I am thinking 1. I either have air in the line... in which case how do I check or correct this, or 2. my pump is not working. What and where should I go from here?