What Causes a Diesel Generator to Hunt and Accelerate?

Diesel generator hunting and acceleration is a common problem that can be caused by a number of factors. If you are experiencing this issue, it is important to troubleshoot the cause so that you can find a solution.

What causes a diesel engine to surge?

Idle engine surging is usually often caused by a fault with the fuel supply, air leak, or the governor system. The carburetor, governor, or filer may need to be cleaned, overhauled, or adjusted.

It is possible that a surge is caused by an issue with fuel amount (known as “running lean”), fuel pressure (the unit that governs fuel pumps and regulators), limited fuel injectors, or even excessive vacuum leaking fuel into the engine.

What causes generator frequency fluctuation?

When the generator is under heavy use, the frequency of the generator may fluctuate. Occasionally, the diesel engine sounds as though it is straining or hunting. It’s possible to observe the frequency fluctuating on the control panel if this auditory fluctuation persists.

What would cause a diesel engine to hunt?

“Hunting” refers to an engine that will keep a constant speed when the throttle is fixed at a certain setting.

This can be due to an issue with the governor system, fuel supply, or air leaks are the most common causes of engine hunting and surging at idle. Carburetor cleaning/overhaul, governor adjustment, and/or air filter replacement may be necessary.

Why does a generator surge?

Fuel surges may be produced by a number of factors, including improper fuel, low gasoline levels, or poor quality fuel. For most generators, utilizing fuel outside of their specifications might result in operating concerns, such as surges.

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Related Questions and Answers

How do you fix voltage fluctuations?

Voltage fluctuations may induce light flicker in humans. Connecting the load at a higher nominal voltage level is one way to do this. Dedicated lines for these kinds of loads are used to provide them; To isolate supplies for fluctuating loads from those for continuous loads, a three-winding transformer may be used.

Why is my generator going high and low?

Because of problems with air and high pressure, the generator turbo isn’t always able to run at full capacity. Additionally, fuel filters and gasoline tanks might get clogged, preventing the generator from receiving a steady flow of fuel.

What does it mean when an engine is hunting?

The continual rotation of the engine is necessary for hunting engine power. An improper stall valve situation or anomalous air volume in the fuel injection pump may cause the engine rpm to fluctuate constantly.

What is DG hunting?

During the phenomena of idle hunting, the engine’s speed (measured in RPM) deviates from its average position (i.e. the idling speed). In idle hunting, if the engine’s speed exceeds the mean speed, it consumes more gasoline than normal.

What does a governor do on a diesel engine?

An important function of a generator governor is to ensure that the unit’s speed remains constant under all load situations, whether such requirements are imposed on the generator itself or external.

What causes under speed in a generator?

When the load on the prime mover exceeds its capacity to match the necessary output, an under-frequency event occurs. Either the load exceeds the generator’s capacity or there is a problem with the primary mover.

How do you test an overspeed trip on a generator?

A speed adjuster may be used to increase engine speed with no load to test it. The gasoline supply will be shut off at 115 percent of the regular speed if you go too fast.

How do you stop a power surge from a generator?

During a hurricane, unplug everything. When using sensitive electrical devices, use appliance-grade surge protectors. Consider putting up a surge protector for your whole house. Have your wiring checked by a professional electrician and affordably reduce your carbon footprint by purchasing energy-efficient equipment.

How do I make my generator run smoother?

Keep extra fuel and Oil filters on hand. Don’t overwork the power source and make sure you’re using high-quality motor oil. Don’t keep bad fuel around and check your oil regularly.

What causes a diesel engine to run rough and stall?

A blocked or malfunctioning fuel pump, which transports gasoline from the tank to the fuel injectors, might result in a rough idle, sputtering, stalling, or even a sluggish start. Rough idling might be caused by an obstructed fuel filter.

What causes white smoke in a diesel?

Injectors are the most common cause of white smoke coming from the exhaust. It is common for white smoke to signal that the diesel fuel is not burning properly. Diesel fuel that has not been consumed will exit the exhaust system in an unburned state.

What happens if the voltage is too high?

Premature failure of electrical and electronic components (e.g. circuit boards) may be caused by overheating when the voltage is too high. Overheating may have long-term and permanent effects on your health.

How do you adjust the governor speed on a generator?

Using a flat screwdriver, insert it into the yellow governor control screw. An adjustment screw may be found on the governor linkage. When making adjustments, keep an eye on the tachometer. Engine revolutions per minute (RPM) may be increased or decreased by rotating the screw counterclockwise or clockwise.

What RPM should a generator run at?

A generator’s output frequency is determined by the engine’s speed. Most engines run at 1800 or 3600 RPM to generate 60 Hz energy. There are pros and disadvantages to each. In big generators, the most frequent and least cost alternator configuration is an 1800 RPM, four-pole set.

Why is my generator not producing full power?

The alternator’s loss of residual magnetism and a faulty AVR or other excitation component is the most typical reasons for a generator not generating electricity. If the voltage on each phase is between 50 and 70 volts, then the AVR may need to be replaced.

How can the power of a generator be increased?

Find the accelerator pedal. When a generator does not have a voltage dial, this is normally located on the side of the generator, or at the top of the generator that does. It’s commonly stamped with “RPM.” You may improve the amount of power you produce by raising the RPMs.

What controls the speed of a diesel engine?

The speed of an automobile is determined by the driver’s control of the engine’s power. In an off-highway diesel engine, the operator just has to manage the engine’s speed to generate power.

Why does my generator shut off after 30 minutes?

To start your generator properly, make sure the choke is all the way down in the maximum choke position. Half choke and then run posture are required after a few minutes. If you don’t make these modifications, the generator will shut down because of an imbalance between air and fuel.


If your diesel generator is hunting or accelerating, make sure to stop the generator and find an answer to the problem as soon as possible.

When a diesel generator is hunting, it will search for the next speed setting. When it finds that speed setting, it will accelerate to that speed.

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James Sylvester
About James Sylvester

James S. Sylvester is an experienced OSHA Safety Supervisor with years of experience in the construction and oil & gas industries. He focuses on workplace safety, occupational health and safety systems. Learn more about James' here or connect with him on Twitter