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Power loss costs thousands

Justin Keller for Progressive Forage Published on 30 October 2017
Checking the level of valve recession

In the near future, the infrastructure of the power companies will not be able to handle the load. As we all know, it seems we are all at the end of the line when it comes to power.

Sure, some have thought ahead or purchased a generator because of a significant loss due to an unexpected power outage. From the machines we use to the products we store, we will always have a need for power in our day-to-day business.

Have we taken the proper steps to prepare for the outage? Has the generator been tested? When was the last service? When was the battery replaced? Is the fuel clean? Are the air filters clean? There are many complex components that require maintenance to keep the generator ready for the outage.

Safety first

Always follow safety recommendations from the maintenance manual for all services and repairs. Perform lock-out, tag-out procedures of all potential power sources prior to maintenance. And please note, this article is not intended to substitute for a qualified technician or maintenance recommended by the manufacturer.


Will your generator start when it is called for? The number one call for generator failure to start during an outage is a failed battery. Whether it is discharged due to a failed charger or is just over two years old, the battery is the starting point to failure. A weak battery causes component damage to starters and electrical boards. It also can build up hydrogen faster than it can vent it.

This can cause an explosion if there is a spark. Clean the battery terminals, check how tight the terminals are, and perform a visual inspection to determine if the battery is swollen. Replacing the battery with a high-quality battery every two years will help ensure the engine will crank when it is called to start.

Shut off utility power to the charger prior to disconnecting cables. Some chargers will burn up if they are disconnected with utility power present.

Oil and filter

When was the last oil and filter change? The manufacturers of all generators have a maintenance schedule. This schedule was not created to sell you parts or cost additional money. Simply put, it costs less to service the engine properly than it does to replace or rebuild it. An annual oil change helps relieve the system of contaminants as a result of engine combustion. Oil and the oil filter for most diesels should be replaced at 200 hours. There are exceptions with large oil pans.

The operation and maintenance manual will assist with the recommended interval for the event of an extended run. We know the oil “looks clean”; however, taking an oil sample can tell you what other contaminants are in the oil. It will also indicate the viscosity (thickness) of the oil.

If the oil is too thin, it may pass the rings and burn, causing increased oil consumption. Selecting the proper oil for the engine is very important as well. In fact, an oil too thick may cause seals or gaskets to push out or even a delay in oil getting where it needs to go, causing potential engine damage.

Proper oil and filter changes can be the difference between the engine’s ability to last for weeks or only minutes during an outage.

Cooling system

We may be servicing the engine annually, but are we servicing what we need to? While the entire generator needs serviced and cleaned, the most skipped maintenance is the cooling system. Yes, the battery is the number one call for no-start; however, number two is cooling system issues. From radiator caps to block heaters, the cooling system has a lot of components that wear out.

Simply put, they were designed to keep the temperature at the manufactured temperature for efficiency and emissions. But hoses degrade, clamps stretch, thermostats stick, belts crack, and coolant … well, it does a few different things. Coolant can become caustic, meaning it can eat aluminum or copper, which causes expensive replacement of radiators and housings. It also separates.

Water leaves the glycol and causes corrosion in the system (rust on steel). The additives in the coolant drop out, causing cavitation erosion on water pumps, liners, housings, heater elements and engine blocks. Changing the coolant with whatever the local supply house has may not be the coolant for your application. If they have only gas coolant, an additive may be required to keep the cavitation erosion from occurring.

Fuel check

During summer, we may fuel the generator and have it serviced, but is that fuel ready for winter as well? If we are lucky, we will have a summer without a power outage. If that is the case, the only fuel we will burn from the generators will be for weekly testing. This means the summer fuel will not be conditioned for winter (unless ordered from the fuel company that way).

Replacing the filters and testing the fuel just before winter helps determine if we have contaminants in the system and what the fuel condition is. Contaminants such as water in a fuel system can be very detrimental to the system. Algae (typically a bacterial or fungal type) has the ability to grow with water to contaminate fuel very quickly.

Additives can be dangerous to living organisms – humans, livestock, pets, birds – as it kills the natural bacteria used in digestion (which can be fatal). A fresh fill-up with fuel helps prevent algae growth without the harmful chemicals lying around.

The load test

While testing the generator weekly or monthly under load is suggested, many generators go through an unloaded test. With a diesel generator, this test should be at no less than 30 percent of the generator’s nameplate kilowatt load. The reason for this is to keep the wet stacking (buildup of unburned fuel in the exhaust) to a minimum.

This also has a cleaner combustion, helps keep the carbon buildup on valves and rings down, and gets the system up to temperature.

If the load will not support this, a load bank should be brought in to verify the generator’s capability to produce load, keep the engine cool, clean the exhaust system and pressurize the cylinders to the maximum. It is always better to find the failure before the emergency.

Advanced testing and generator maintenance should be performed by an experienced technician. Insulation resistance testing, breaker testing, thermal imaging and transfer switch testing should be performed annually to trend readings and help with predictive maintenance.

With proper maintenance, we can keep our equipment moving to provide success during an outage. While there are failures of components, many component failures can be attributed to maintenance practices.  end mark

PHOTO: Using a valve recession tool, generator technician Joshua Greer checks the level of valve recession, where valves get pushed out of position due to pressure from the pistons. Recession causes wear on the valve head and, if not replaced, can cause more expensive damage later. Photo by Carrie Veselka.

Justin Keller
  • Justin Keller

  • Product Support Sales Rep
  • Western States Equipment Co.
  • Email Justin Keller