Why Your Generator Might Be Acting Up
So your generator won’t start. Or maybe it’s running rough, sputtering like it’s got a cold. Before you panic and call for expensive repairs, here’s the thing — the problem might be sitting right in your fuel tank.
Bad fuel is actually one of the most common reasons generators fail when you need them most. And honestly? Most people don’t even think about it until something goes wrong. If you’re dealing with backup power equipment, knowing what bad fuel looks like can save you serious headaches down the road.
Whether you’re running a standby generator at home or powering equipment for your business, Fuel Delivery Services in St. John VI can help you maintain fresh fuel supplies. But first, let’s figure out if your current fuel is the culprit.
The 7 Warning Signs of Degraded Fuel
1. Your Fuel Looks Dark or Cloudy
Fresh diesel has that clear, amber color. Gasoline looks kind of pale yellow or light amber. Pretty straightforward, right?
When fuel goes bad, it darkens considerably. Diesel turns almost black or develops a muddy brown color. Gasoline gets darker too and might look cloudy or hazy. If you pull a sample from your tank and it looks nothing like what you poured in months ago, that’s your first red flag.
2. There’s Visible Sediment or Particles
Grab a clean glass jar and draw some fuel from the bottom of your tank. Hold it up to light. See any floating bits? Stuff settling at the bottom? That sediment is oxidized fuel breaking down into gunk that’ll clog your filters and injectors fast.
This happens naturally over time. Fuel reacts with oxygen, and the chemical compounds start falling apart. Once you’ve got visible sediment, you’re already past the point of easy fixes.
3. The Fuel Separates Into Layers
Water contamination is a huge problem, especially in humid environments. When water gets into your fuel tank — through condensation, bad seals, or contaminated supply — it doesn’t mix with fuel. It sinks to the bottom and forms a separate layer.
According to the Environmental Protection Agency’s fuel quality standards, water contamination causes microbial growth and accelerates fuel degradation significantly.
Check for that distinct separation line. If it’s there, you’ve got problems beyond just old fuel.
4. It Smells Sour or Rancid
Good fuel has that sharp, pungent smell we all recognize. Bad fuel? It smells off. Kind of sour or stale. Some people describe it as almost varnish-like.
Trust your nose on this one. If the smell makes you think “that’s not right,” it probably isn’t. The chemical breakdown that causes discoloration also produces different compounds that change the odor profile completely.
5. Your Generator Struggles to Start
Here’s where the rubber meets the road. Bad fuel doesn’t combust properly. It’s lost volatility — basically the stuff that makes it ignite readily.
Your generator cranks and cranks but won’t catch. Or it catches briefly then dies. Reliable Fuel Delivery Services in St. John VI can prevent this frustration by ensuring you always have properly stored, fresh fuel on hand.
6. The Engine Runs Rough or Stalls
Maybe your generator starts, but it sounds terrible. Rough idling. Surging. Unexpected stalls under load. These symptoms often point directly to fuel quality issues.
Contaminated fuel doesn’t burn evenly. Those sediments we talked about? They clog fuel filters partially, causing inconsistent fuel flow. The engine gets fuel, then doesn’t, then does again. That’s your rough running explained.
7. You’re Seeing Black Smoke or Unusual Exhaust
Excessive black smoke means incomplete combustion. And incomplete combustion often means bad fuel. The engine can’t burn the degraded stuff properly, so unburned particles go right out the exhaust.
This isn’t just an efficiency problem. Running on bad fuel damages engine components over time. Those injectors and pistons weren’t designed to handle gunk.
How Long Does Fuel Actually Last?
This catches a lot of people off guard. Fuel doesn’t last forever — not even close.
Gasoline starts degrading within 30 days without stabilizer. By three months, you’re likely seeing noticeable quality decline. Six months? Probably unusable for sensitive equipment like generators.
Diesel holds up somewhat better — roughly six months to a year under ideal conditions. But “ideal conditions” means temperature-controlled, properly sealed storage with minimal air exposure. How many generator fuel tanks meet those standards? Not many.
For professional guidance on fuel management and storage solutions, Gentech Generator LLC recommends establishing a regular fuel rotation schedule based on your specific usage patterns and climate conditions.
What To Do When Fuel Goes Bad
Assess the Damage Level
Slightly darkened fuel with no sediment? You might be okay adding fresh fuel to dilute it. But fuel with visible contamination or separation needs to go. Don’t risk your equipment.
Drain and Dispose Properly
Bad fuel requires proper disposal. Don’t dump it — that’s illegal and environmentally harmful. Most auto parts stores and recycling centers accept old fuel. Some fuel delivery companies handle disposal too.
Clean the System
After draining bad fuel, replace your fuel filter. That filter probably caught a lot of contamination. Running fresh fuel through a clogged filter defeats the purpose.
For severe contamination, consider having the tank professionally cleaned. Sediment accumulates on tank walls and bottoms. Simply draining doesn’t remove everything.
Start Fresh With Quality Fuel
Now fill up with good, fresh fuel from a reputable source. Fuel Delivery Services in St. John VI ensures you get properly stored, quality fuel delivered directly to your tank.
Preventing Future Fuel Problems
Prevention beats dealing with bad fuel every time. Here’s what actually works:
- Rotate your fuel supply — Use and replace fuel regularly rather than letting it sit indefinitely
- Add fuel stabilizer — For fuel that’ll sit more than a month, stabilizer additives help significantly
- Keep tanks full — Less air space means less condensation and slower oxidation
- Schedule regular deliveries — Reliable Fuel Delivery Services in St. John VI makes maintaining fresh fuel supplies simple
- Test periodically — Check your fuel visually every few months before problems develop
For additional information on generator maintenance and fuel management best practices, keeping detailed records helps track your fuel’s age and condition.
Frequently Asked Questions
Can fuel stabilizer fix fuel that’s already gone bad?
Nope. Stabilizers prevent degradation — they don’t reverse it. Once fuel has broken down significantly, stabilizer won’t restore its original properties. Think of it like sunscreen; great for prevention, useless for treating a burn.
How often should I run my standby generator to keep fuel fresh?
Running your generator monthly for about 30 minutes under load helps cycle fuel through the system. But this alone won’t prevent all degradation in the tank. Combining regular operation with scheduled fuel rotation works best.
Is it safe to mix old fuel with new fuel?
Slightly aged fuel can be diluted with fresh fuel — maybe a 1:4 ratio of old to new. But visibly contaminated fuel? Don’t mix it. You’ll just contaminate your fresh supply and potentially damage your equipment.
Why does my generator fuel go bad faster than my car’s?
Your car uses fuel constantly, cycling through tanks quickly. Generator fuel often sits for months between outages. That extended storage time, combined with tank conditions that allow more air and moisture exposure, accelerates degradation.
What’s the best way to store generator fuel long-term?
Use quality containers or tanks with tight seals. Store in cool, temperature-stable locations away from direct sunlight. Add appropriate stabilizer immediately when filling. And honestly, the best approach is avoiding long-term storage altogether through regular fuel delivery schedules.
Keeping your generator running reliably comes down to fuel quality. Now you know what to look for and what to do about it. Your backup power system will thank you when the next outage hits.
