When Your Generator Won’t Start, Check the Carburetor First – It Could Save You Hundreds in Repairs

Nothing is more frustrating than discovering your standby generator won’t start during a power outage. While many homeowners immediately assume the worst – expensive engine damage or electrical failures – the culprit is often much simpler and more affordable to fix: carburetor problems. Understanding how to diagnose and prevent fuel system issues can mean the difference between a quick repair and a costly generator replacement.

The Hidden Enemy: How Fuel Problems Develop

As engines age or sit unused, any fuel left in the carburetor can turn into gum and varnish, causing various problems. Furthermore, gasoline stored in a can for more than 30 days must be discarded, as it too begins to turn into varnish. Today’s fuels contain MTBE and alcohol (ethanol), which degrade quickly. When fuel sits too long, it begins to evaporate and oxidize, leaving behind sticky residues, gum and varnish, that cling to the carburetor’s tiny jets and passages. Over time, those deposits choke the flow of fuel, much like cholesterol blocking your arteries.

As gasoline ages, it can turn into varnish, clogging the passageways inside the carburetor and preventing sufficient fuel from reaching the engine. This problem accumulates over time. Each time gasoline sits, the varnish builds up gradually, similar to layers of paint, until fuel flow is obstructed.

Warning Signs Your Carburetor Needs Attention

Recognizing carburetor problems early can save you significant repair costs. The generator won’t start at all. It starts but runs rough or surges. It stalls shortly after starting. You smell strong fuel vapors or notice leaks.

When this occurs, the engine may either fail to start, run only with the choke engaged (which limits air intake and alters the fuel/air mixture), or run with surges. If your Champion 3750 generator runs briefly then dies, inspect the carburetor float and needle valve for sticking or debris. A clogged fuel filter or old fuel can cause starvation.

Diagnostic Steps for Fuel System Problems

Before calling for professional help, there are several diagnostic steps you can take. If you can’t get your engine to turn over after several tries, remove a spark plug. The tip of the plug should be wet if the engine is getting proper fuel flow. However, if it’s dry, there’s likely a break in the transfer of the fuel.

To remedy a fuel system issue, first start with checking the fuel cap vent for any clogs. If all looks well with the fuel cap; check the fuel tank for sediment, bad fuel, etc. If the gas tank is full, but no fuel is getting to the carburetor, there may be a problem with the fuel line or fuel valve. The fuel valve controls the flow of fuel from the gas tank to the carburetor. Make sure that this is set to OPEN to allow fuel to flow into the proper channels.

Professional Carburetor Cleaning and Repair

While some maintenance can be performed by homeowners, carburetor cleaning often requires professional expertise. In most cases, the carburetor needs to be removed from the engine. Clean all parts with carburetor cleaner and blow out all small holes and passageways with compressed air. Remove all non-metallic parts, as carburetor cleaner can deform and clog them over time.

For residents in North Carolina dealing with generator carburetor issues, professional services like Generator Repair Orange County, NC can provide expert diagnosis and repair. ESP has now evolved into a “Service Contractor.” Response to our customers’ needs drives our company. The typical client has a situation that requires immediate attention now, not at the contractor’s earliest convenience. Our service contractors respond to your needs immediately.

Prevention: The Key to Avoiding Carburetor Problems

The best approach to carburetor issues is prevention. Use fresh gasoline without ethanol for small generators. Drain fuel tanks if the generator will be idle for over 30 days. Clean carburetors regularly to prevent clogging. To avoid this in the future, try to run your generator at least once a month, and never store it for long periods of time without draining the gas tank and the carburetor first.

Run your generator under load for about 30 minutes every month. This helps to keep the engine lubricated and ensures that the generator is in working condition. It also helps to prevent fuel from becoming stale and clogging the system. Conducting load tests monthly or quarterly prevents “wet stacking”—a buildup of unburned fuel in the engine that reduces efficiency.

Fuel Quality Matters

Opt for fuel from reputable stations such as Shell, BP, Sonoco, Phillips 66, etc. I do not recommend using Speedway gas. Bad gas can cause a multitude of problems, now and in the future. Pro tip: expired gas has a different odor than fresh gas, so if your fuel has gone bad, you’ll probably be able to smell the difference.

Fuel should be stored in a clean, dry tank with stabilizers to prevent degradation. All fuel sources should be kept cool and dry. Most fuels have a resident design life and should be monitored for degradation and actively treated according to the supplier’s specifications.

When to Call a Professional

While some maintenance and troubleshooting tasks can be performed by the owner, there are many situations where calling a professional is the safest and most effective option. Professional technicians have the expertise, tools, and training to handle complex issues and ensure your generator operates safely and efficiently.

Over 70% of repairs in our lawn mower business stem from this same issue. You likely have dirt, gum, varnish, etc., clogging the small passageways and jets in your carburetor. Professional diagnosis can quickly identify whether your problem is truly carburetor-related or if there are other underlying issues.

The Bottom Line

Carburetor problems in standby generators are largely preventable with proper maintenance and fuel management. By running your generator regularly, using quality fuel, and addressing issues early, you can avoid the frustration and expense of major repairs. Customer satisfaction is important to us. We want you to speak directly to a service representative and not an answering machine. Your problem may seem small, but at ESP it will always receive the attention that it deserves.

Remember, when your generator fails to start, don’t panic – check the basics first. Often, what seems like a catastrophic failure is simply a clogged carburetor that can be cleaned and restored to proper function, keeping your home powered and your family safe during outages.