Generators provide essential backup power during electricity outages. Knowing how to quickly diagnose and fix common generator problems ensures your generator functions effectively when you need it most. This guide will walk you through simple troubleshooting techniques for the most widespread generator failures.
Understanding Common Generator Problems
These issues cause most generator malfunctions:
Battery Failure
Generator batteries provide initial ignition to start the engine. Weak or dead batteries prevent ignition and fail to turn over the motor. This issue is common after batteries wear down or expire.
Failure to Start
When powered with good batteries, generators that fail to start suffer from other ignition problems. Faulty spark plug connections, no fuel, or engine oil issues can all prevent startup.
Stalling
Some generators run initially but stall shortly after starting. This signifies deeper generator engine problems like bad fuel, low oil, or cylinder wear.
Clogged Fuel Lines
Fuel filters and lines that become dirty or clogged make it impossible for fuel to reach the engine. Without gas flow, generators starve and shut down.
Low Coolant Levels
Overheating is a leading cause of generator failure. Coolant leaks or neglecting to refill coolant creates overheating issues that stall generators to prevent engine damage.
Fuel Depletion
Generators quickly deplete fuel stores during extended outages. Allowing fuel tanks to fully empty causes temporary shutdowns until generators are refilled.
Pinpointing the specific problem is the first step toward getting generators running again. So let’s walk through the full troubleshooting process next.
Step-by-Step Generator Troubleshooting Guide
Follow these key steps when diagnosing common generator problems:
Step 1: Check Battery Charge and Voltage
Use a multimeter to test battery charge percentage and voltage. Check the battery posts and cable connections while testing. Typical issues found:
- Dead batteries or weak 12V charge
- Corroded or loose battery terminals
If batteries test well, move to the next step.
Step 2: Check Engine Oil Level
- Locate oil dipstick, pull it out, and wipe clean
- Reinsert fully and pull dipstick back out
- Check that oil level falls between “Full” and “Add” markers
- Top off oil if low
Adding oil sometimes fixes generators that fail to start.
If the oil level looks full, proceed to the next test.
Step 3: Check Fuel Level and Quality
- Shake fuel tank and listen for sloshing gasoline
- Remove fuel filter cap and smell for gas fumes
- Drain fuel into a container to check for contamination
- Add fresh fuel if tank is empty or contaminated
If fuel is present and clean, move to spark plug inspection.
Step 4: Inspect Spark Plug
- Remove spark plug cable and use a spark plug socket to access plug
- Examine spark plug electrode and porcelain for wear and carbon buildup
- Check spark plug gap spacing using a gap tool (0.6-1.0 mm for small engines)
- Replace spark plug if excessively worn or gap is too narrow/wide
Healthy engines should produce blue sparks across plug gaps. No spark means further electrical testing is needed.
If the spark plug is good, proceed to filtration and venting tests.
Step 5: Check Filters and Vents
- Remove air filter and examine for dirt or oil saturation
- Blow air through fuel filters to clean out debris if present
- Clear any obstructions found around cooling vents or ducting
- Pour clean fuel and replace fuel filters if blocked or contaminated
- Replace air filters yearly or after excessive soiling develops
If ventilation pathways are clear, perform throttle body testing next.
Step 6: Test Throttle Body Operation
- Locate throttle body assembly and linkage under air filter
- Check for binding in throttle linkage or cable
- Trigger throttle open using linkage while manually choking air intake
- Feel for strong intake suction. Weak vacuum indicates leakage
- Tighten loose linkage connections or replace faulty throttle body
Sluggish throttle response makes starting difficult. Binding throttles prevent sufficient air intake as rotations per minute (rpms) increase.
For generators still not starting, cylinder and valve train inspection comes next.
Step 7: Compression and Leak Down Testing
- Remove spark plug cables and all but one spark plug
- Screw compression gauge into the open spark plug hole
- Pull starter cord with throttle wide open until compression stabilizes
- Note gauge measurement (80-200 psi is acceptable depending on size)
- Repeat test on other cylinders, checking for anomalies
- Conduct a leak-down test if low compression is found on a cylinder
Losses of 25% or greater during leak-down signal burnt exhaust valves or blown head gaskets. Seek repair assistance for mechanical engine issues.
This covers most small generator troubleshooting. For additional help with large diesel and complex generators, consult authorized technicians.
Also Read: Why Every Household Should Have a Portable Generator
Preventive Generator Maintenance Tips
Beyond troubleshooting failures, preventive maintenance keeps generators working reliably for years. Follow these upkeep guidelines:
Daily:
- Check fuel and oil levels
- Inspect battery connections
- Clean around intake and exhaust vents
After Each Use:
- Allow the generator to fully cool down
- Wipe exterior clean of dirt and debris
Every 3 Months:
- Clean fuel injectors and replace fuel filters
- Change the oil and replace the oil filter
- Drain old gas and add fresh fuel
- Inspect and gap spark plug
Annually:
- Deep clean generator exterior
- Test battery charger and trickle charger
- Replace air filters
- Drain and flush fuel tank completely
- Change coolant fluid
- Check/tighten bolts, clamps and connections
- Record hours run to track maintenance schedule
Document all maintenance activities and inspections. Tracking provides warning of impending part failures before total breakdowns.
Staying on top of generator care prevents many roadside headaches. But when trouble does strike, use our step-by-step troubleshooting guide to get things humming again.
Knowing When to Call for Generator Repairs
For home generators, DIY troubleshooting can resolve the most common problems. However, serious unit issues often require technical expertise to properly diagnose and fix. Consider calling in professional technicians if you encounter:
Electrical System Faults:
- Short circuits
- Bad transfer switch operation
- Faulty control boards
Mechanical Failures:
- Knocking cylinders
- Leaking gaskets or seals
- Cracked heads or engine blocks
Natural Gas Issues:
- Gas valve failures
- Major gas leaks
- Damaged flexible gas lines
Don’t take chances with dangerous gas leaks, exposed high-voltage wiring, or hazardous spilled fluids. Reputable dealers have certified staff to handle tricky generator repairs.
They also possess programming computers that interface with modern microprocessor-based generators. This high-tech equipment diagnoses problems undetectable through standard testing alone.
So employ the troubleshooting guide to tackle straightforward problems first. But for complex generator issues, trust certified technicians to get you back up and running at peak performance.
Also Read: How to Protect Your Appliances in a Power Outage
Conclusion
Generator troubleshooting keeps backup systems operating reliably whenever emergencies cause power failures. Knowing the most common problems generators face allows for quick diagnoses of issues. Compression testing, spark inspections, and filtration cleaning can solve many basic equipment failures at home.
But generators contain dangerous high voltages and require great care when inspecting and handling. Seek qualified generator technicians to safely address major component or gas line problems beyond routine maintenance procedures. Use this guide’s preventative generator care tips and troubleshooting steps to keep essential electricity flowing in any blackout situation.