I have a brand new Chinese mini excavator. About 4000 lbs, 25 HP engine, only 2 hours on the unit. On flat concrete it moves forward, reverse fine. If I try to turn left right, or dig with the bucket, in other words, when ever I put a load on it the engine bogs down and dies. The engine runs fine, gets great rpm, no issues with the engine from what I can tell. It has not enough power to pull itself even up a tiny little grade. Hydraulic levels are great, all lines are tight, no leaks anywhere. Since it is brand new I cannot believe the filter is blocked. I was told to check the return line but and not sure how to check the intake from tank to pump or the return line.
Were there any manuals that came with it?
No, there was not. I have contacted the company via their website but they are little to no help. They simply produce the units and ship them around the world with no intent (apparently) to do customer service. They have manuals for other models using the same motors pumps etc, but those manuals are so basic they don't address issues at all.
Just from what you posted, I wonder if the engine is getting full fuel flow under load. Just because the machine is new doesn't mean garbage, rust, or even dirt from when it was being built isn't causing an issue in your fuel system. The fact you can't get decent support from the company on a new machine indicates a lot of cut corners. I assume this was purchased on a RB site like Iron Planet or GovPlanet? Personally, I would definitively rule out fuel and air issues before you start digging into hydraulics or such. Double check your fuel and air filters to ensure they look clean. Without a manual you may have to trace the lines from the tank to the fuel pump and loosen them to see if flow is good. If gravity fed, diesel should flow freely. If not, you may need to add 3-5 psi to your fuel tank to ensure flow is good. Lots of ways to do that will expandable pipe plugs and/or Schrader valves.
Thanks for your reply. Yes I did get it via a big auction company. A friend recommended this manf to me so I guess I got "hooked" by it all. Yes, I am checking those things. I was also told to check the hydraulic return line, that flow may be restricted somewhere.
If you have a restricted hydraulic system, the engine would bog down from any movement like raising the arm or curling the bucket. But from your post, it sounds like the engine is bogging down only when you put a load on it from driving the machine or trying to dig. Does the engine bog down from any free movement of the hydraulics or only when you put a load on the hydraulics like trying to dig ? What happens if you have the boom and dipper extended full up, then lower it quickly down to the ground? If a hydraulic restriction, the engine should bog down. If an engine issue, gravity assisting the falling boom will have a different, or much lesser, effect on bogging the engine down.
Perhaps your friend should be on the hook trying to fix it.
Wouldn't that be cool. Anyway, two weeks ago when I first started checking it out at home, when not under a load everything worked, bucket, arm, reach, swing boom etc. All moved smoothly, but when I went to use it and put things under a load to actually turn, or dig that's when i discovered it would bog down and kill the engine. I have checked the things you guys mentioned and there is nothing obviously showing as a problem. However, today I went to fire it up for further checking, now, even when just sitting with no load, the engine at high rpm, when i raise/lower the blade, move the boom or bucket, the engine bogs down with virtually no load on it. The engine doesn't die, but it almost dies. So, based on your info I am thinking you must be right, it is in the hydraulics somewhere.
I hear ya but I'm not completely convinced it's hydraulics as you could still have a fuel system that is just getting worse and worse. The only other advice I can give is to toss a pressure gauge on your hydraulics and verify you're getting full pressure that bogs down the engine. Probably just put a gauge on a tee inline between the hose and a cylinder on your boom or stick. A small, simple 5000 psi pressure gauge is just $10 on amazon. Keep posting your symptoms and findings here. Lots of hydraulic experts should chime in. Best of luck on it.
New Chinese equipment comes with many faults right from the factory. This isn't the first thread about this kind of thing and won't be the last.