Bobcat 873G: Troubleshooting High Throttle Bogging Down

[MikePhua]

The Bobcat 873G is a popular skid steer loader widely used in construction, landscaping, and other heavy-duty industries. Known for its powerful hydraulics, high lifting capacity, and versatility, the 873G is designed to tackle various tasks with ease. However, like many machines in this category, it may experience performance issues, such as bogging down at high throttle. In this article, we will explore the possible causes of this issue, provide troubleshooting steps, and suggest solutions for restoring the machine’s optimal performance.
Introduction to the Bobcat 873G Skid Steer
The Bobcat 873G is part of the renowned Bobcat family of skid steer loaders. It is equipped with a 70-horsepower engine, which allows it to handle a wide range of attachments and materials. The 873G has a rated operating capacity of 2,400 pounds and features an efficient hydraulic system that maximizes its lifting and digging capabilities. Its compact design makes it ideal for working in tight spaces, while its robust frame and high ground clearance ensure stability on rough terrain.
Common Performance Issues with the Bobcat 873G
While the Bobcat 873G is known for its reliability, it can experience issues that affect its performance. One of the more concerning problems is when the engine bogs down at high throttle. This issue can occur during full acceleration or while performing tasks that require the machine to work at full power. Below, we’ll explore some potential causes and how to resolve them.
Possible Causes of Bogging Down at High Throttle

1. Clogged Fuel System
   • Symptoms: The engine struggles to reach full power and may eventually shut down when running at high throttle.
     
   • Causes: A clogged fuel filter or fuel line can restrict the flow of fuel to the engine, causing a drop in performance. Over time, fuel impurities, dirt, or water can accumulate in the system, leading to a blockage.
     
   • Solution: Begin by checking the fuel filter for any signs of clogs or contaminants. If the filter appears dirty, replace it. Inspect the fuel lines for any blockages or leaks. Drain the fuel tank and replace it with fresh, clean fuel to eliminate any water or dirt in the system.
     
2. Faulty Air Filter
   • Symptoms: The engine may sputter or lose power at high throttle, especially under load.
     
   • Causes: A clogged or dirty air filter can restrict airflow to the engine, reducing its efficiency. This issue is more prominent when the machine is working hard, such as during heavy lifting or moving materials.
     
   • Solution: Inspect the air filter and replace it if it is dirty or clogged. Ensure that the filter is properly seated and there are no holes or cracks in the housing that could let dirt or debris into the intake system.
     
3. Fuel Injection Problems
   • Symptoms: Bogging down at high throttle, poor fuel economy, or uneven engine performance.
     
   • Causes: If the fuel injectors are clogged or malfunctioning, the engine may not receive the right amount of fuel, leading to a drop in power. Faulty injectors can also cause poor combustion, leading to a rough running engine.
     
   • Solution: Have the fuel injectors cleaned or replaced. In some cases, it may be necessary to use a fuel injector cleaner additive or perform a professional cleaning service to restore proper function.
     
4. Ignition System Malfunctions
   • Symptoms: Intermittent loss of power or bogging down, particularly when the engine reaches higher RPMs.
     
   • Causes: A worn-out spark plug, ignition coil, or malfunctioning distributor can result in poor combustion, causing the engine to struggle under load.
     
   • Solution: Inspect the spark plugs and ignition system. Replace any worn or damaged components, including spark plugs, ignition coils, or wires. If the ignition system is not functioning properly, the engine may not be firing correctly at high throttle, leading to poor performance.
     
5. Low Engine Compression
   • Symptoms: Power loss at high RPMs, excessive engine noise, or difficulty starting.
     
   • Causes: Low compression can be caused by worn-out piston rings, damaged valves, or a malfunctioning head gasket. This issue reduces the engine's ability to generate enough power to perform heavy tasks.
     
   • Solution: Conduct a compression test to assess the engine’s health. If compression is low in one or more cylinders, it may be necessary to replace the piston rings, valves, or head gasket, depending on the specific issue.
     
6. Hydraulic System Problems
   • Symptoms: Slow or unresponsive hydraulic movements, bogging down under load, or the engine struggling to maintain high RPMs.
     
   • Causes: Hydraulic issues, such as low fluid levels, a clogged hydraulic filter, or a malfunctioning hydraulic pump, can place additional strain on the engine, causing it to bog down.
     
   • Solution: Check the hydraulic fluid level and ensure it is within the recommended range. Replace the hydraulic filter if it appears dirty or clogged. Inspect the hydraulic pump for any signs of wear or malfunction, and ensure that the system is properly pressurized.
     
7. Exhaust System Blockages
   • Symptoms: The engine may start to bog down when it reaches high throttle, especially when the exhaust system is under load.
     
   • Causes: A clogged or restricted exhaust system, particularly the muffler or catalytic converter, can cause backpressure, reducing engine performance.
     
   • Solution: Inspect the exhaust system for blockages or signs of damage. Clean or replace the muffler and catalytic converter if necessary.
     

General Maintenance Tips for Preventing Bogging Issues

1. Regular Fluid Checks: Ensure that engine oil, fuel, and hydraulic fluids are changed on schedule, and always maintain appropriate fluid levels.
   
2. Proper Filtration: Regularly inspect and replace the air filter, fuel filter, and hydraulic filters to prevent contaminants from affecting performance.
   
3. Spark Plug and Ignition Maintenance: Periodically check the spark plugs, ignition wires, and coils to ensure proper ignition and combustion.
   
4. Keep the Engine Clean: Regularly clean the engine compartment to prevent dirt and debris from interfering with the engine’s operation.
   
5. Scheduled Inspections: Perform routine inspections and maintenance checks to identify issues early. This includes checking for leaks, unusual sounds, or changes in performance.
   

Conclusion
The Bobcat 873G is a powerful and reliable skid steer loader, but like any heavy equipment, it may encounter issues over time. If your 873G is bogging down at high throttle, it is important to troubleshoot the underlying causes, which can range from fuel system problems to ignition issues. Regular maintenance, including fluid checks, air and fuel filter replacements, and spark plug inspections, can help prevent many of these issues and keep the machine running smoothly. By addressing any problems promptly, you can maintain the performance and extend the lifespan of your Bobcat 873G, ensuring it continues to deliver optimal results on the job site.