I am looking for possible causes for high fuel usage on my Onan Diesel Generator. I am burning in excess of 1.5 gallons per hour on my 10KW unit. I should be burning about n.5 gallons per hour on half load. My generator has 5000 hours on it. I pulled off the top and front covers today to check the generator end bearing as I have been told that when they start to go, the generator works real hard and will consume allot of fuel. The bearing looks good. I also cleaned out the spark arrestor and ran it an hour or so. Since it starts right up and I do not have excessive crank time, I am thinking that the valve adjustments are fine but may be an injector issue. Does anyone know if there are adjustments on these Onan Diesels injectors? By the way mine has an Isuzu motor. I appreciate any opinions.