What To Do When Your Mini Excavator Won’t Start

Whether you rented a mini excavator out or own one, a common problem people face (especially during the winters) is that the mini excavator doesn’t turn over or start. Knowing how to work a mini excavator is one thing; starting it up early morning is an entirely different story.

Of course, working the mini excavator on your own will save you time and money, but can end up costing you even more if something goes wrong. So, what does it mean when a mini excavator won’t start? How do you troubleshoot it? If it ran perfectly yesterday, what’s wrong with it now?

The first thing you need to do is try again, and this time, listen for any clicking sounds as you crank the key. If it doesn’t start, it doesn’t necessarily mean that you ended up costing yourself tens of thousands of dollars. There could be a problem with the spark plug (condensation, battery, or a simple clog). But how do you determine what’s wrong? Let’s get into more detail to find out!

Why a Mini Excavator Won’t Turn Over

Mini excavator won’t start
Mini excavator won’t start

When you twist your mini excavator’s key, there are two possibilities:

  1. The engine doesn’t crank. Basically, nothing happens when you twist the key. There could be a safety feature preventing start-up or a technical issue here.
  2. The engine cranks but doesn’t start up. There could be a handful of issues to deal with here.

Let’s discuss the two in more detail.

Twisting the Key But the Engine Doesn’t Crank

There are a large number of safety features built into mini excavators. Before you try to start your mini excavator, the first thing you need to consider is the shift lever position. This is a safety mechanism introduced in many different models, especially the 6th, 7th, and 8th generation mini excavators:

Orange stick zero position on instrument panel in cabin of machinery
Orange stick zero position on instrument panel in cabin of machinery

This safety mechanism is there to ensure that the engine doesn’t start when in gear. The sudden push you experience in this case may damage your surroundings or potentially hurt someone. Due to the raw power a mini excavator has, there is also a chance of the axle breaking in this case.

Move the lever a few times to check and make sure it’s in neutral gear. Try again.

If it still doesn’t start, you may have to temporarily bypass this switch. Be very careful when bypassing it. Here is how to do it:

  1. Find the safety switch between the floor board and the bottom of your mini excavator’s clutch pedal.
  2. Use a 1/4-inch (or whatever size the lock nut is) open-end wrench. Turn the nut counterclockwise to loosen it.
  3. (OPTIONAL) With a crescent wrench, turn the screw underneath clockwise until it is clear of the clutch. This will give you more room to work.
  4. Use a pair of wire pliers to cut the black and red wire coming from the switch. Strip the wires.
  5. Connect both wires together and make sure the connection is tight.

And you’re done!

If, however, the problem is not with the shift lever, take a look at the battery. There may be some white substance on the battery connectors. This can either be lead sulfate or anhydrous copper sulfate. If that is the case, disconnect that battery and clean both terminals.

If you can, check the voltage of your battery. Either use the main panel or a multi-meter. You can find these at battery posts if you don’t have one. This will help you eliminate a large number of potential issues.

Next, check the battery switch and circuit breaker on the side of your mini excavator. A tester (screwdriver) should be enough for this. Make sure the battery is connected when testing. Have someone crank the engine while testing the voltage as well. It would then be either:

  • 0. If this is the case, the problem is somewhere in the battery or its connector. The ignition switch circuit may also be faulty.
  • 0-8. In this case, the battery may need replacement. Start the mini excavator with an alternate battery. Check to see if the generator is working and charging the battery.
  • 8-12 volts. Here, you may have a seized starter or engine. There is too much resistance in the circuitry. Try to find an overheating wire. If there is none, you have yourself a major expense in your hands.
  • >12 volts. This means the battery isn’t your problem; it’s the starter. You will likely find rust or corrosion on the starter.

If you have a seized engine, stop cranking, else you might end up damaging something else in the process – for example the pistons.

The Engine Cranks But Doesn’t Start

Now, let’s consider the other option. Your engine cranks like it would normally, but it doesn’t start up. If this is happening to you, tread lightly. Don’t over-crank it or you might just end up flooding the engine with fuel, among other problems. Use 5-8 second bursts and wait 15 seconds between each attempt.

Since the engine is cranking, battery isn’t an issue.

Diesel engines run on four things; air, fuel, compression, and an engine computer (ECU).

If you worked with the mini excavator one day and are trying to start it the next day, air isn’t the issue. If, however, it’s been a while since you started it, check for a clogged air filter or blocked exhaust. Condensation plus dust can do that to mini excavators.

Dirty air filter
Dirty air filter

If the excavator was running yesterday without any smoke, compressor is not the issue, either. If, however, there was smoke, you have yourself an oil leak and the compressor might be flooded. It’s time to call the professionals, then. If it was running without smoke, compression isn’t the issue, either.

Fuel clogs or closed supply valves are a common issue with mini excavators left out in the open. You may have a closed or pinched O-ring, or may have accidently bumped against a shutoff valve.

Start by inspecting valve positions around the fuel tank and the oil filter. It happens – even to professionals so this isn’t anything to be ashamed of. And while you’re at it, consider checking the fuel levels as well.

If you think you are comfortable doing it, try to pull out the fuel pipe near the filter. Once out, open the valve and see if you have sufficient fuel flow. If the fuel is slow, you have yourself a clog.

Clogs end up reducing the RPM on your excavator, not allowing it to run properly. Clogs may be air or frozen fuel. Inspect the fuel pipes thoroughly to get rid of these clogs.

These sum up some of the most common issues that arise in mini excavators – especially those that you can check and fix for yourself. If you are still unable to start your mini excavator, chances are that something major is going on under the hood and that you should let professionals handle it.

About Charlie D Paige

Charlie is a massive DIY fan, with dozens of DIY projects under his belt - ranging from tiling to electrics, and concrete pads to walls. Charlie loves tinkering, seeing how things works, the outdoors and playing with power tools... so is it any wonder that he's completed so many DIY jobs over the years?

Charlie loves spreading his hard-won DIY experience with the world via this blog.