Hi Folks- I have a very old Deutz F3L912 in a trencher. The Injection Pump failed a few years ago and I had it rebuilt. Now; a few years later a couple of the piston springs inside the injection pump have broken. So; I bought a rebuilt pump and went through timing hell. Now the engine starts up normally, but I can’t control the RPM. It goes from an idle to full throttle and everywhere in between. The throttle control has no effect on the RPM. The fuel supply is good and the steel injector lines and injectors are new. I have searched the fuel system for air leaks and found nothing. I wonder if it’s possible that the pump must be internally bled. Any thoughts would be much appreciated.
Do the numbers on the old pump match those on the new pump EXACTLY.?? If they don’t have tamper laquer on the bolts, remove the side cover and try running the pump by hand, using the pumps control rack.. It’s possible that if u got a pump “off the shelf” the rack is stuck..or u can reach around and pull the manual shut off lever to see if the rack is moving..
Thanks much. I will try that. Much appreciated. Gonna be a couple of days, but I'll let you know. Thanks again.
Sorry for the delay in posting. I finally got the unit in the shop and was able to test the rack. The rack works smoothly with the fuel shutoff lever but does not move with the throttle control lever. The throttle control lever has spring pressure from inside the rear housing and moves smoothly with full cycle. Again; moving the throttle control does not move the rack I've tried various positions of the rack by using the shutoff control and the engine starts each time, the runs for 2 seconds and quits. There is a good fuel supply going to the pump. Any advice would be very much appreciated. Thanks.