I am talking with a guy that has a 4106 that he says will sputter at about 20 mph, then take off and run good. He says he was told it sounds like water in the fuel. Any other ideas on what it could be? Fuel filter? What could the worst case for this be? Im interested in this bus, but don't want to travel several states to look at something that I could rule out with your experience. It has a auto trans if that matters?
I doubt the water theory probably air or the fuel pump getting weak
good luck
If the fuel pump was "getting weak", it would not accelerate any better above 20 MPH. It would be interesting to check the fuel pressure at the final filter(easy to do) it should be 50-70 LBS>(65 average) at 2000 RPM, min. at idle 35. I'm wondering if it has the RPM modulator installed (easy to remove)as used in California to minimize smoke during acceleration off the line.>>>Dan
Thanks very much for the information. I was also told that it could be a air flap? Would any of these harm it to drive it?
Forget the "air flap", can't happen per your description.>>>Dan (I would look for dirty fuel filters)
Maybe his "sputter" is bad injector, burned valve/s, needs tune up... See if he could send you a video and sound clip of engine idling to speeding up at rear of coach