I just got my 4bt running and had to thank you guys. All of you that guessed low pressure to the injector pump were right. The 4b came with alot of the parts in a box, to make things worse I bought two motors and the second engine's loose parts were also in the same box. I was missing the banjo bolt for the line from the filter to injection pump. I only had the bolts from the lift pump to the filter. The threads matched so I put them both in, my good motor. I didn't know that they had different size orfices, until I looked at a 3rd 4bt. I bought a new bolt and copper washer, bled it out and it lit up after a few tries. Hope this helps someone else out someday. Erik