Replacing John Deere D140 Fuel Pump: Step-By-Step Guide

The John Deere D140 is a lawn tractor that has been in production since at least 2013. While the D140 is generally reliable, some owners have reported issues with the fuel pump. This guide will outline the steps to replace the fuel pump on a John Deere D140 lawn tractor.

Check for output at the pump's outlet

To check for output at the pump's outlet, you will need to perform a fuel pressure test. This will help you determine if the fuel pump is functioning properly and providing enough fuel to the engine. Here is a step-by-step guide:

• Prepare the Settings: Connect a digital multimeter to the positive and negative terminals of the fuel pump. Ensure there are no broken circuits between the fuel pump and relay.
• Switch Ignition: Insert the key into the ignition and turn it on without starting the engine. You should hear a soft whirl sound, indicating that the pump is ready to supply fuel to the engine.
• Test Negative Terminals: Split the circuit into two parts, separating the ground phase from the positive side. Use a jumper wire to power the fuel circuit and activate the pump. Now, connect the digital multimeter to the negative terminals of both the battery and the pump. Conduct the test using a live circuit wire. If the meter shows a reading of more than 0.1, it indicates a loss of voltage power due to damaged harness connectors or poor wiring.
• Test Positive Terminals: Connect the digital multimeter to the positive terminals of the pump and the battery. Also, test the output terminal of the fuel pump to ensure it is functioning correctly. If the voltage drop exceeds the recommended reading of 0.1 volts, it confirms that the harness connectors or wiring is faulty.
• Obtain a Fuel Pressure Gauge: These are commonly available at auto parts stores and are useful for most vehicles. If you cannot purchase one, consider borrowing one from a machine shop or auto shop.
• Locate the Fuel Pump Test Point: The fuel pump test point is usually located near the fuel injectors and the connection between the pump and the filter injector rail. There should be a separation joint or a test port where you can attach the pressure gauge.
• Rev the Engine: With the engine slightly warmed up, check the pressure at idle speed and the rated speed specified in your pump specifications. If you don't know the rated speed, simply rev the engine and observe the pressure reaction. If the needle doesn't move or moves below the specifications, it indicates a problem with the fuel pump, and it may need to be replaced.

It is important to consult your owner's manual for specific instructions, as the location of the fuel pump and test procedures may vary depending on your vehicle's make and model. Additionally, always take the necessary safety precautions when working on or testing the fuel system.

Check the vacuum line for tears

To check the vacuum line for tears, you will need to perform a thorough visual inspection of the vacuum system. This includes checking all the lines, hoses, and connections for any signs of damage or wear. Look for cracks, splits, loose fittings, or disconnected lines. Pay close attention to areas where the hoses pass near hot engine components or sharp edges, as these are common spots for vacuum leaks to occur.

If you have difficulty locating the vacuum lines in your engine, you can refer to the label under the hood, search for information online, or consult your owner's manual. It is important to inspect all vacuum lines to ensure you identify any potential issues.

In addition to the visual inspection, you can perform a smoke test or a spray test to check for vacuum leaks. For the smoke test, you will need a smoke machine to introduce smoke into the system. If there is a leak, the smoke will escape and be visible, making it easier to identify the source of the leak.

The spray test is a simpler method that involves spraying water over the suspected leak area. If there is a vacuum leak, you will hear the water being sucked into the engine. This test is particularly useful for identifying larger leaks caused by cracks in the vacuum lines that may be difficult to see during a visual inspection.

It is important to note that vacuum leaks can have negative consequences for your vehicle's performance and fuel efficiency. Therefore, taking the time to thoroughly inspect and test your vacuum system is crucial to ensure optimal vehicle performance and prevent further complications.

Check for fuel flow while the engine is cranking

To check for fuel flow while the engine is cranking, you must first establish whether your John Deere D140 is fitted with a fuel pump. If it is, then you should be able to observe fuel flow while the engine is cranking with the key. If there is no fuel pump, you should still get a steady stream of fuel to the carb.

If there is no fuel flow, then you should investigate the fuel pump. Check for output at the pump's outlet. The pump is likely either vacuum-actuated or electric. You could also check that the vacuum line to the pump is intact.

Check if the starter motor spins the engine

To check if the starter motor spins the engine of your John Deere D140, you can perform the following checks:

First, check if there is any action when the key is turned. If there is no response, the starter may have died.

Next, check if the fuse is blown. If so, replace it with the correct amp fuse. Ensure that the battery is fully charged, and the mower is disengaged.

You can then try the following: flip the key on and off, and check if the fuel solenoid clicks. If it does, the key switch has voltage. You can also try to jump from the battery terminal to the switch terminal, which is a quick way to check the battery, cables, starter solenoid, and starter.

If there is still no response, you may have a cable problem. Check the voltage at the starter with a voltmeter.

If the above steps do not work, you can try to direct jump the solenoid, bypassing everything. If the solenoid does not close, then there may be an issue with the voltage at the solenoid.

If the engine can be turned 360 by hand, then the problem may lie with the starter or the solenoid.

Finally, if you have access to another known good battery, try replacing the battery to see if that resolves the issue.

Check the carburetor

To check the carburetor of your John Deere D140, you can refer to the user manual for detailed directions and safety information. However, here are some general steps and tips to help you get started:

Firstly, it is important to identify the issues with your carburetor. Some common signs of carburetor problems include a poorly running engine, saturated spark plugs, and a broken o-ring. If you notice any of these issues, it is important to address them promptly.

Before checking the carburetor, ensure that you have the necessary knowledge and skills to perform the inspection safely and effectively. If you are unsure, it is recommended to seek assistance from a qualified technician or refer to the John Deere how-to maintenance videos and other resources on their website.

When inspecting the carburetor, pay close attention to the o-rings, gaskets, and other components for any damage or wear. For example, the o-ring that seats the tower in place in the bowl for the solenoid plunger may be broken, or the o-ring on the top side of the float may be pinched. Replacing these o-rings and gaskets can help resolve issues with the carburetor.

Additionally, consider using a carburetor cleaner or additive, such as Techron, Seafoam, or STP, to clean the carburetor and remove any built-up debris or contaminants. This can help improve the performance of the carburetor and resolve issues such as a slow sputter at mid-throttle.

It is also important to check for other potential causes of carburetor issues, such as a bad spark plug, a clogged air filter, or choke problems. Addressing these issues in a timely manner can help ensure the optimal performance of your John Deere D140 equipment.

Frequently asked questions