john deere 120 Excavator is the larger version of John deere 110 excavator. It has an engine of 143 horsepower, which makes this machine absolutely powerful enough to dig through hard soil or clay.

john deere 120 excavator Low oil pressure

I have a John Deere 120 Excavator, and it is giving me a low oil pressure warning. It says it is at 5psi. The machine has been sitting for about 3 years and the battery was dead. I charged the battery, turned on the machine, and that is when I got the low oil pressure message.

I changed out the oil and filter today and ran the machine for about 30 minutes with no success. I started it up this morning and let it run for another 30 minutes. Still nothing.

The engine sounds good, no abnormal noises or excessive smoke from the exhaust. The only issue I can find is that there seems to be a small amount of oil leaking from one of the hoses going into the water tank on top of the engine (the hose closest to the cab). It has been running fine up until now.

john deere 120 excavator

john deere 120 excavator No oil pressure

The ecm is reading an oil pressure value that is too high, so it’s shutting down the engine. I’m going to assume you do not have access to the service manuals and proper tools to diagnose this problem. You will need to take it to a dealer and have them check it out.

1. Oil pressure sensor or harness is defective

2. Oil pump drive gear is broken

3. Crankcase oil is low

4. Oil pump suction strainer is clogged

5. Crankshaft bearings are worn or damaged

6. Camshaft bearing is worn or damaged

7. Oil filter is clogged or bypassing

8. Oil pump shaft seal is leaking

john deere 120 excavator Engine performance problem

Most excavators have an engine that is liquid cooled. This means that there is a radiator and a cooling fan. The fan has to work to pull cool air through the radiator so the radiator can cool the engine. The cooling fan is controlled by an electric motor. If either of these components goes bad, it can cause the engine to overheat and shut down.

The fan motor may be stuck on or stuck off. Both are problems since one will cause loss of coolant flow and the other will cause the engine to overheat. On Caterpillar machines, we use a thermistor that controls when the fan turns on and off. There is also a relay that controls the excitation voltage to the cooling fans electric motor. If either of these units are bad, it would make your machine overheat.

john deere 120 excavator Engine runs rough or low power

The john deere 120 excavator Engine runs rough or low power can be caused by a faulty fuel injection pump. The pump needs to be removed and rebuilt.

We have seen some pumps that have a stuck pin within the rack housing. This pin can be removed and the pump will function correctly.

The governor is another potential cause of this problem. There is an idle cam on the governor that can become worn, causing the engine to run rough during idle. It is difficult to adjust injection timing with this part worn, which will cause engine performance issues. It is best to replace this part when worn.

john deere 120 excavator Engine starts then stops

I’ve been working on a ’95 John Deere 120 for a friend of mine. It started with an issue where it would run fine for a while, then just shut off and not start back up. I replaced the fuel pump and filter, and after that it was running great. Then the final time I went to work on it, it wouldn’t start at all.

I got a new battery, tried jumping it with my truck, and still nothing. It turns over fine, but will not fire. I checked the fuel to make sure there’s no blockage in the line between the pump and injector, but still nothing. Has anyone else had this issue?

john deere 120 excavator Hydraulic System problems

The john deere 120 excavator Hydraulic System problems include the occurrence of oil leaks from the main pump, swing gearbox, and swing pinion. The seals and O-rings on the parts will age after a long time of service and cause oil or hydraulic fluid to leak out, resulting in reduced working pressure or even failure. The accumulator pressure is low.

The accumulator may be damaged, the gas may be discharged, or the gas may evaporate due to long-term use. At this point, we must first check whether there is any damage to the accumulator seal and whether there is any oil leakage at the joint of the cylinder head. If there is no problem with the above, it means that it needs to be replaced with a new oil-gas separator.

Incorrect operation during assembly will also cause damage to parts. The working pressure reaches its rated value during operation, but there is no output power. This phenomenon indicates that the control valve has failed and needs to be replaced with a new one.

john deere 120 excavator Control valve malfunctions

A malfunctioning control valve can cause a variety of different problems. If the machine will not start, check to ensure that the control valve is in neutral. If the hydraulic system does not function properly, check the pump and control valves for obstructions.

The John Deere Model 120 excavator features an electrical system that uses a 12-volt battery to power the machine’s starter motor. The engine’s alternator powers the rest of the electrical components, including light fixtures and gauges.

A blown fuse may result from an electrical problem such as a short circuit or an overloaded circuit. The fuse box contains individual fuses for each electrical component on the machine. To locate a blown fuse, remove each fuse and inspect it for burn marks or other signs of damage.

john deere 120 excavator Travel system malfunctions

Make sure all the components of the travel system are properly lubricated. The hydraulic pump has a relief valve that is used to set its pressure. This valve should be adjusted to the proper pressure setting. Check the hydraulic lines and hoses for wear and make sure they are not leaking or plugged.

If the hydraulic system is working properly, but the machine is still not moving, look for broken or worn drive chains, drive sprockets, rollers and idlers. Replace any parts that are damaged or worn. If you are getting no power from the engine to the track, you may have a stripped gear in your final drive or a broken ring gear in your differential.

Make sure that both tracks are moving at the same speed by looking at them from behind the machine while it is traveling around a turn. If one track is moving faster than another, look for a bent guide wheel or track roller frame for that side of the machine. This can cause slippage of the track on that side of the machine, which will cause it to move slower than usual.

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