excavator kx161-2

[ykman]

I have a 2003, kx161-2. v2203 engine. I purchased it with head gasket gone, did a overhaul ,new head gasket and head. I bought it with blown engine. I have been a year chasing a power issue, when I lift the boom and or curl the bucket it will bog the engine down like its overloading the hydraulics. It will drop the rpm 500 rpm. Any experience people have a take , opinion or another thread to help me track this down. new member here

 

[North Idaho Wolfman]

Do you have the WSM for the unit?

They usually help quite a bit in getting to the bottom of hydraulic issues.

This site is good, I've gotten several manuals from them.

http://kubota.servicemanualvault.com/Kubota-KX161-2-Excavator-Workshop-Manual.html

 

[ykman]

yes, I do have the manual but im not finding it helpful

 

[Digger Dager]

ykman,

Welcome to the forum.

Sounds like a pinched hose or a foaled up fitting. Might also double check that the plumbing is going to the right places.

Digger

 

[North Idaho Wolfman]

Yep hoses crushed/ pinched would make the most since.

Are the control for the boom and bucket that your having the issue with the same stick / control?
If so it could be a linkage, socket, connection issue there that's causing 2 things to happen at the same time that shouldn't.

 

[lugbolt]

Tons of possibilities here.

LS valve. Restrictions. Hoses. Pumps. Engine. Pump drive. Pilot valves.

You're going to need a lot of troubleshooting skills and probably access to a flow meter and set of pressure gauges among other things.

I've seen an SVL90 with a LS valve issue, had the pump at full stroke at all times, similar complaint (and kind of jerky operation as well).

I've seen an SVL with an engine problem, exact same symptoms. Had a KX040 with a broken/failed engine coupling, low power complaint.

 

[ykman]

this comment, is the road I have been chasing so thank you for that. I have went thru the control bank. I backed all main relief valves to 3700 psi. I did this on pump a1 p1 and p2. I then set the overload reliefs to the exact or as exact as I could get with a gauge that goes up in increments of 50. I then set the relief valves back to the manual specified pressure. Two things were odd. control b6 and b5 were opposite of each other. Meaning 5 was where 6 should be an vice versa. Or at least when I set them they reacted that way so that was puzzling. But after they were all set, I gave it a whirl turned down my governer screw so it was (just) putting out black smoke ( I did this as I have been replacing fuel system parts chasing this problem too.
I gave it a run and well it seemed ok, I curl the bucket it dropped maybe 50 rpm and extend the bucket maybe 50. I then lifted the boom an lost 100 rpm. Problem seemed corrected. I let it cool overnight came back today and curl the bucket drop 600 rpm and so on and so on. I am led to believe that its like 'something' is pushing hydraulic oil against itself-- if that makes any sense. Someone mentioned LS ( I assume load sensing valve. This machine does not have I do believe but) maybe a expert can help me further on this direction cause that as well would make sense. AGAIN my hope was that someone maybe been down this road and knows of a knutot valve or a flipper doohickey that maybe gave them trouble. Thanks guys

 

[ykman]

oh as well when I extend the stick right out and curl it in it reacts the same. I capped the boom Lines off and I as well get a similar reaction. What absolutely doesn't do it is blade right up or down, nor does the swing if I pin it seem to do it It mostly seems to be main functions only ( so I assume) from what I can tell is that it is the main pump or something that controls it. However it seems the main pump if putting out Plenty of pressure.

 

[boz1989]

Had someone out with a big excavator once, he had a similar problem. What he finally figured out, was the diesel in his transfer tank was bad. How long has the machine sat, how old is the fuel.

Sent from my LGMP260 using Tapatalk

 

[ykman]

injection pump sent out rebuilt and calibrated, as well as injectors. fuel filters twice. new fuel lines front to back. Ran through four tank of fuel. Injection timing is at 17 to 19 depending on how quick your stop turning the engine.

 

[North Idaho Wolfman]

How does it react when you run the track motors?

 

[ykman]

Although I have done that minimal, loading it on the trailer it pretty near stalled

 

[North Idaho Wolfman]

Have you put a pressure gauge on the pump and monitored it while working it?

It's really sounding like a relief / over pressure issue.

 

[ykman]

I tend to , although I dont know. Agree with you. I am not sure where to begin. I have thoughts the pump isn't relieving but where does it relieve? all my relief pressures are set butu it still seems to die. any thoughts were to start putting gauges in