John Deere 790 Problems

We all are aware of what John Deere offers. They offer some best-in-class mower models with sturdy construction and proper maintenance. However, they are also bound to develop issues due to mechanical components.

All mechanical parts are bound to have some problems with use and aging. No matter how much effort you put into the proper care of your mower, you will likely experience some setbacks while mowing your lawn.

With age, some parts of the hydraulic may worn out over time. Therefore, it may need proper maintenance and repair from time to time for optimal performance. Most of the John Deere 790 are bound to develop problems with their hydraulic systems.

Therefore when the equipment or any component malfunction, you want to troubleshoot and try to fix it on your own before visiting an authorized service center and spending thousands of dollars. In this article, I am giving you some problems along with the east fixes that can help prevent setbacks while mowing your lawn.

7 John Deere 790 Problems

John Deere 790 Front Axle Problems

If your John Deere 790 isn’t moving for whatever reason, there might be an issue with the front axle. If the front axle looks spinning, it could be just because of a flat or stuck tire. On the other hand, operator error or forgetting to release the brake can also be the problem of front axle issues in cars.

When you go incline, you should look at foreign objects that may hinder your John Deere 790 if you encounter an impact. We haven’t found any easy cause or solution for cars’ front axle problems. You should take your unit to an authorized dealer or service center for proper diagnosis and fix.

John Deere 790 Fuel Solenoid Problems

All John Deere 790 carburetors have a solenoid chamber that fills with fluid. When this solenoid device is engaged and energized, it flows the fuel from the room mixes with air while passing through the passage of the carburetor.

Therefore, if you stop the engine, the solenoid power will likely be removed while closing the fuel line. Therefore, your John Deere 790 engine faults or stops. If the solenoid power is lost while your John Deere 790 engine is running, it will soon shut down due to a fuel supply cutoff. Below are some symptoms of fuel solenoid problems in cars.


  • Trouble Cold-starting
  • Engine Shuts Off
  • Erratic Idling 
  • Hesitant Or Improper Acceleration

Solenoid’s actual & only purpose is to allow or stop the gas flow. Thus, your John Deere 790 may not even start if it fails. Therefore below are some causes and solutions for fuel solenoid problems in mowers. 


When the engine is running, the tip of the solenoid becomes soft and comes off very quickly. After that, it is bound to be sucked up in the carburetor jet port while shutting off a large amount of fuel supply, resulting in the engine stalling or not having enough Power to start. 


To solve this issue, you first need to remove the solenoid using the rubber cap on its end. Gently pull the rubber cap; if it comes off easily for whatever reason, the solenoid needs a total replacement.

John Deere 790 Head Gasket Problems

If you address any head gasket problem early, repairing will be easy. It would help if you managed all kinds of symptoms that indicate a gasket problem in John Deere 790 at an early stage. Sometimes cork, metal or plastic, or rubber seals get compromised.

With a John Deere 790, the fix is expensive if you need to visit an authorized service center. However, if you know the symptoms and signs of lousy gasket problems, you can fix it and restore your John Deere 790’s operation.

Below I am mentioning a few characters, causes, and solutions that will keep you from facing these setbacks. In most cases, symptoms like smoking, failure to start, loss of firepower, or oil leaks can be caught & fixed early without much effort or expense.


John Deere 790 Will Not Start: If too much combustion force is escaping through your John Deere 790’s engine, there might be poor Compression.

Due to the lack of momentum in the crankshaft to keep the piston moving up and down, your John Deere 790 may still need to start. You might notice your mower briefly sputtering before going silent again if poor Compression is not fixed early.

Insufficient Power: if your John Deere 790 is a few months old, you might already have experience cutting the same area of grass regularly.

If you notice the John Deere 790 requiring extra time to cut the same area of grass you used to cover in a few minutes, it clearly shows a reduced power output from the John Deere 790 engine.

Since blade speeds and the mower are directly linked to the engine power output, any problem with power generation will prevent the John Deere 790 from starting. In this case, the gasket may be blown out.

Low Compression: if your John Deere 790 has low Compression, there is no doubt why there is a problem with its head gasket. Getting your unit to a small engine Store and having one of the mechanics carry out the test using gauges is essential.

Even an auto garage can be helpful with testing the compression level of your John Deere 790. The John Deere 790 with good Compression should have at least 55-60 pounds per square inch pressure. If the gauge shows a lower value, the blown head gasket might be blown out.

Oil Leaks: A worn-out gasket will also hinder its ability to block off oil coating the engine cylinder. Oil leaks can be a sign of a worn-out gasket as well. Therefore look for this symptom if you suspect anything wrong with the gasket.

Smoke: In a few cases, you will notice excessive smoke in the exhaust due to a blown-out head gasket. Other than this, smoke can be accompanied by leaking oil. The actual cause of the smoke is oil burning off the cylinder’s combustion chamber. 

What To Do?

Undoubtedly, the number one cause of a worm-out gasket tends to be an overheated motor. Due to the engine heat, the gasket cracks and ruptures over time. Apart from this, if you have modified your John Deere 790 that uses a liquid engine coolant, check the level and fill it up when needed on a routine basis.

On the other hand, if the mower has air coolant, keep its cooling fin clear and clean from all kinds of blockage and obstruction. Another thing to note is the sufficient oil level in the mower.

With time, a gasket can be damaged due to wear and tear. You will need to replace the gasket from time to time. Unfortunately, most manufacturers compromise with specific components to take shortcuts and alleviate their margins.

The only way to ensure you have a genuine part that will last for a prolonged period is by purchasing a component from the authorized dealer or the mower’s manufacturer itself.

john deere 790 hydraulic problem

Almost all models of John Deere have some hydraulic issues. Transmission problems can be very frustrating, especially when you mow your lawn. Any hydraulic transmission issue will reduce your mower’s ability to get up steep hills or slopes, even if the engine is running and fully functional.

Finding the actual problem can be a daunting task and complicated. Depending on the exact condition of your transmission, fix or replace it entirely if it’s under warranty. Sometimes, changing its fluid does the work.

You should also check the drive belt for damages. If the drive belt slips off the pulleys, it will stop your mower from moving correctly. This is not a transmission problem, but it can feel like one.

John Deere 790 Loader Problems

If the boom rises very slowly or does not rise, there might be a loader problem. This problem usually arises when there is a bucket or boom overload. Other costs can be auxiliary circuits on over-relief or low oil flow from the pump.

Also, look at this cylinder shaft for any damages or wear. If the pump is damaged or has control linkage binding, loader problems may arise. Other possible reasons for John Deere 790 loader issues include valve spool binding.

John Deere 790 Starting Problems

Starting problems in John Deere 790 are common and irritate most users. Apart from this, finding the reason for the John Deere 790 starting problem can take a lot of work. Being a noob, you may not even help yourself to see the actual cause of why this problem keeps arising. 

Generally, starting problems occur when the engine help needs to be improved. Other than this, if the fuel capacity of your mower is slower than before, it could be the culprit of the engine not starting.

Insufficient or old oil residue stuck in the drainage or tank may also create mower nog. Sometimes an operational error results in this issue. Ensure the clutch PTO is off, and the pedal does work properly. If all these are incorrect or according to, your mower wheel may rotate but not turn to move. There is an easy fix that I have discussed below.

The Fix:

  • Firstly, inspect the situation and condition of your John Deere 790 engine. If there is any damage, address it first.
  • Secondly, call your mechanic for proper troubleshooting and maintenance of a John Deere 790. There might be a problem with the connections or cable attachment to the junction, and you cannot find it.
  • Thirdly, make sure you also inspect the filter of the fuel. If it is noticed as hazy, there might be drainage in the tank. Make sure to clean it off and remove any previous fuel residue.

Last but not least, you should always look over the clutch of PTO by opening the hood & finalizing troubleshooting. If the case is defective, fix it according to the manual.

John Deere 790 Battery Problem

If your John Deere 790 battery is old, defective, or inefficient, replace it with a new one. Apart from that, battery problems may also arise if there is a problem with the charger itself. If the charger has a problem, you cannot charge your mower. You can quickly fix the charger with basic electrical skills or visit your nearby mechanical shop.

Final Thoughts

There are a lot of things that you need to do to ensure your John Deere 790 performs optimally. It is essential to keep your John Deere 790 hydraulic system in perfect shape and work optimally for a prolonged period.

To achieve this, you should always pay attention to regular maintenance of your John Deere 790 and work with a reliable hydraulic repair company. I tried to give you all the John Deere 790 problem information.

If you like this article, then do share it first. Your share will help many people learn about the fundamental issues of mowers and health and choose the better one. Do check our other articles on mowers. See you in the next post, till then take care and goodbye.

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