I need some help with my 220. when digging, walking, swinging, pretty much any function it doesn't "ramp up" for lack of a better description. This leads to using the machine at full throttle and still only able to use the hydraulics in small steps to keep from bogging or even killing the engine. Any help with diagnosing the problem or if someone has had this problem and knows what is causing it would be greatly appreciated. The engine seams to run fine but it doesn't get the necessary throttle up when using the hydraulics heavily, or there is a relief valve that doesn't open to allow the engine to catch up?
Is this the SK220 Mark III? or Mark II ... been awhile since I've worked on Kobelco. Might be able to help or share some ideas. For starters, Hydraulic Filters, Engine Fuel and Air Filters in good condition? Are you able to take any pressure readings off the Main Hydraulic Pump and Pilot Pump? Normally i would think if the pump is not up-stroking or "ramp up" in your terms the engine shouldn't bog down since the flow-rate is at minimum even if the pump reaches stall pressure (5100~5300 psi) Now in your case, you have both slow movements (this could mean the pump swash plate is at minimum displacement) and the engine is bogging down (main relief pressure might have been set too high, bad filters, fuel problem, engine problem) But safest bet is to try and get some pressure readings. I believe there's a solenoid on the pump, try getting some voltage measurements to the coil of the solenoid (try working with the solenoid connected and disconnected to see if any change in performance in noticeable Some more info could help pin-point this cause, but let's start with machine model or serial #.
sorry for the confusion, the machine will operate at full speed, I just cant ask it to move all at once or the engine will bog down or die. I will try to get some pressure readings off it, its not a #1 priority so it may take a day or two. 1994 Kobelco Trackhoe excavator sk220 serial number LLU0781
Did you check the banjo bolt below the hand primer?? it has a filter screen in it.. take out, remove screen, blow off screen, put back in.. solves 90% of your problems..