I have a Hitachi EX120-2. I fought a fuel issue on it for a while after I first got it and it turned out to be a clogged screen at the Banjo bolt just prior to the fuel filter. The day I cleaned that out the machine ran great for hours. When I shut it down, I had a leaking hose on the boom. It took a couple of months before I got around to pulling the hose for repair. The first month that it sat, I did not realize that the hood had been left open. Once we fixed the hoses and recharged the batteries, it will not run correctly. I will not idle up to full power, and therefore the hydraulics run slow. I do not think it is a fuel issue. I will pull the banjo screen again tomorrow to confirm this, but I am wondering if there is anything that I should be concerned with having left the hood up for a month and leaving the engine compartment exposed to the elements. The machine tries to change the idle when you push the different buttons, there is a slight change in the rpms with each setting, but not much. Could this be as simple as the throttle cable getting some corrosion and binding up? While it sat, the side window was left open as well. Could this be an electrical issue in the cab from exposure to rain?
Just disconnect the cable/linkage from the injection pump throttle & use an adjustable wrench to move the throttle manually.. That will eliminate or confirm your suspicions of the inj. pump.. & move on from there..
Thanks for the suggestion. I did not suspect the injection pump, but that will be on eof the steps I will use to check on the throttle cable.
Hi Knightgang, First thing I would do is listen to pumpguys advice quick way to eliminate what the issue is. As for the banjo screen clogging... once they start to clog it usually means there is getting to be a good amount of crud in the fuel tank and this will cause clogging regulary, best thing to do is try to flush the tank out as best you can. Water on the controls... well water is never too good for anything electrical... personally I would rip the control apart and clean up anything I found to be questionable and go about some preventive measures also.. but this depends on your level of confidence in dealing with electronics... anyways start with pumpguys directions and go from there
Knightgang, did you ever figure out your issue? I have a similar issue. I have a ex120-2. It ran fine, kinda sputtered and died. At that point we changed the fuel filter and water separator and still wasn’t getting fuel. Then
Read on the banjo bolts and cleaned all of them out and at that same time heard something about manually putting m8 bolt In throttle and see if it runs that way. This was all while sitting a month. Manually holding throttle while someone starts I can use my hand and run it however I want if I stay up there but have no throttle control inside. What I don’t know is if the original problem was related to the throttle ec or stepping motor or if I had a fuel issue to begin with and while it sat it developed the second issue. Now I just pulled the panel behind the seat. I checked the four wires on the stepper motor ( if that’s what it’s called) in the back compartment opposite of the battery and and have no voltage there with key on or off. So now I’m trying to find the issue stopping power to the motor. Once again I can run it manually but no controls inside. I jumper wired the 4 prong plug behind the seat and got a combination of red light flashes, but still looking to find a key and directions how to read them. Sorry for the split message and long winded message.