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The Bobcat 853 skid-steer loader, powered by the reliable Kubota V2203 diesel engine, is widely used in construction and landscaping due to its versatility and power. However, like all diesel-powered equipment, it can experience fuel system issues that directly affect performance and operability. This detailed article explores common fuel line problems encountered with the Bobcat 853, methods for diagnosing these issues, and practical solutions to maintain fuel system integrity and ensure smooth engine operation.
Fuel System Overview
The Bobcat 853 employs a direct fuel delivery system including fuel lines, fuel pump, fuel filters, and injectors designed to supply clean and steady diesel fuel from a 14.3-gallon tank to the engine. Proper fuel flow ensures consistent combustion and engine power output. The fuel lift pump pulls diesel from the tank through the fuel lines and filters before sending it to the injection pump.
Common Fuel Line Issues
One Bobcat 853 owner experienced fuel starvation symptoms that included sputtering and loss of power. Despite replacing the primer bulb and fuel lines with new parts, problems recurred. Further inspection revealed sediment and partial blockage in the fuel pickup tube inside the tank. Cleaning the tube and ensuring a proper seal to prevent air leaks resolved the issue, restoring reliable fuel flow and engine performance.
Summary
Fuel line problems are a common cause of performance issues in Bobcat 853 skid-steer loaders. Identifying symptoms such as rough running, failure to prime, and power loss helps target inspection efforts toward hoses, filters, pumps, and tanks. Routine maintenance including regular fuel filter changes, tight system connections, and cleanliness practices significantly reduce fuel-related failures. By understanding the fuel system components and maintenance needs, operators can ensure consistent engine operation, extend component life, and minimize unplanned downtime in demanding work environments.
Fuel System Overview
The Bobcat 853 employs a direct fuel delivery system including fuel lines, fuel pump, fuel filters, and injectors designed to supply clean and steady diesel fuel from a 14.3-gallon tank to the engine. Proper fuel flow ensures consistent combustion and engine power output. The fuel lift pump pulls diesel from the tank through the fuel lines and filters before sending it to the injection pump.
Common Fuel Line Issues
- Fuel Starvation: The engine sputters or runs poorly due to inadequate fuel reaching the injectors, often caused by clogged fuel lines, dirty or blocked fuel filters, air leaks in the line, or faulty lift pumps.
- Air in Fuel Line: Causes rough running or hesitation, resulting from loose fittings, cracked hoses, or damaged seals allowing air to enter the system.
- Water Contamination: Leads to corrosion and injector damage, often detected by water separators or accumulation in the fuel filter.
- Fuel Line Blockages: Debris or sediment in the tank or degraded fuel lines restrict flow.
- Check Valve Failures: Improperly functioning check valves in fuel lines prevent fuel priming or cause loss of pressure.
- Engine runs intermittently or stalls under load.
- Engine hesitates or has difficulty starting.
- Fuel lift bulb (primer) does not hold fuel or fails to fill.
- Decreased engine power and rough idling.
- Excessive black smoke during operation.
- Frequent need to re-prime fuel system.
- Visually inspect fuel hoses for cracks, brittleness, or leaks.
- Check fuel filter condition and replace regularly to prevent clogging.
- Test fuel lift pump operation by observing primer bulb behavior—repeat slow filling or failure to hold fuel indicates leaks or pump issues.
- Remove and examine the pickup tube inside the fuel tank for damage, blockage, or debris.
- Loosen the fuel tank cap to eliminate vacuum if suspected to impede fuel flow.
- Verify check valve functionality within fuel lines to ensure one-way fuel flow and priming.
- Inspect for water contamination in the fuel filter or separator using drain valves or clear bowls.
- Replace fuel filters at manufacturer-recommended intervals; early replacement is better when operating in dusty or dirty environments.
- Use clean, quality diesel fuel stored in well-maintained tanks to reduce contamination risk.
- Regularly inspect all fuel lines and connectors for wear and secure fittings to prevent air intrusion.
- Consider installing fuel filters with water separators if not already equipped, for added protection.
- Adopt a fuel system bleeding procedure when air enters the system to restore fuel flow.
- Keep a maintenance log documenting fuel system replacements and inspections.
- Fuel Lift Pump: A low-pressure pump moving fuel from the tank to the injection system.
- Primer Bulb: A manual pump allowing operators to prime fuel lines before engine start.
- Check Valve: A valve permitting fuel flow in one direction only to maintain pressure.
- Fuel Filter: A device trapping contaminants to protect the fuel system.
- Air Leak: Unwanted air intrusion that disrupts fuel delivery and engine operation.
- Water Separator: A component removing water from fuel to prevent engine damage.
- Fuel Injector: Device injecting fuel into the combustion chamber at high pressure.
- Fuel Starvation: Insufficient fuel reaching the engine causing power loss or stalling.
One Bobcat 853 owner experienced fuel starvation symptoms that included sputtering and loss of power. Despite replacing the primer bulb and fuel lines with new parts, problems recurred. Further inspection revealed sediment and partial blockage in the fuel pickup tube inside the tank. Cleaning the tube and ensuring a proper seal to prevent air leaks resolved the issue, restoring reliable fuel flow and engine performance.
Summary
Fuel line problems are a common cause of performance issues in Bobcat 853 skid-steer loaders. Identifying symptoms such as rough running, failure to prime, and power loss helps target inspection efforts toward hoses, filters, pumps, and tanks. Routine maintenance including regular fuel filter changes, tight system connections, and cleanliness practices significantly reduce fuel-related failures. By understanding the fuel system components and maintenance needs, operators can ensure consistent engine operation, extend component life, and minimize unplanned downtime in demanding work environments.
