Serial number is YQU468 My Kobelco 200LC Mark IV is not running good. The rpms are low and the injector pump (throttle) is turned up to the maximum. The RPMs fluctuate up and down. I replaced both fuel filters (twice) and they appeared clean. I replaced the lift pump and that helped for about 3 hours run time. The fuel tank is completely filled up. I think it may be the injector pump -Bosch (Cummins 5.9 engine). I watched UTUBE university how to replace the pump - and it does not look easy (borderline brain surgery). How can I test the injector pump before I throw money at the machine? Thanks for any help.
Hello Hello is there anybody out there???
Might want to put a better description in your thread title like Cummins 5.9 RPM's fluctuating. Lot's more members familiar with Cummins compared to Kobelco. It sounds more engine related than an an issue with what brand machine it's in.
First, is this an inline pump? If so, are you maintaining prime? In other words, does your primary fuel filter lose fuel overnight? Where is the primer pump? Is it on the fuel/ water separator head or is it on the injection pump? If it's a piston primer, is it locked down? Have you measured fuel pressure in the pump. Should be between 45&65 psi. Have you run rubber hoses to the supply and return and run the machine off a 5 gallon bucket of fuel? Is your return fuel aerated or foamy? Are your fuel lines clear of trash in the lines, jammed up at fittings? Have you taken a sample off the bottom of the tank? Could be full of water and leaves.
Post a pic of your injection pump, we can help better. Although, there is a tremendous resource on this site. Thepumpguysc , just a state down from you. Probably tell you all you wanna know about your pump. It's all about how you state your question. Welder Dave hit the nail on the head with his advice.
The 5.9 had both types of inj pumps put on them.. An in-line pump is one where the lines coming off of the pump, going to the injectors, r in a straight line.. And a rotary pump is where the lines are in a circle off the back of the pump.. Some simple checks: Check the throttle linkage for wear.. the ball and clevis become worn and allow the throttle on the pump to move.. If it’s an in-line pump and u turned the throttle STOP IN as far as it’ll go, u screwed up.. it has an internal stop that actually cuts the fuel back if turned in to far..
OK, thanks for the help. I ended up replacing the injector pump (inline Bosch pump) with a used pump and the engine runs much better. The mechanic stated that the internal shaft has weights which were not working to keep the engine RPMs constant. Just reporting back on the outcome.