Top Reasons Why Your Generator Won’t Start

There are several items to check if your used diesel generators won’t start like they should. You should check and troubleshoot it in a certain order to get it started.

Cold Weather Starts

Diesel engines encounter problems when you are starting them in cold weather because several conditions change when the temperatures drop in the winter. The oil in the crankcase thickens in the winter and at the same time, the battery voltage output drops so you have fewer cranking amps to start the engine. It’s a good idea to check the oil dipstick in the generator. If the oil appears thick, you should change your summer oil to a lighter oil. Most businesses run 15W-40, 30 or 40 weight in the summer, but these are too thick in the winter. You can change the oil to a synthetic motor oil or a 10W-30 so your diesel generator will start more easily.

When you buy used diesel generators for sale, the next thing to check in the winter is your battery. You should test it to make sure it is fully charged so it can crank your engine. If it is low, recharge it and check the output of the charging system to make sure it’s at the correct amperage and voltage. Also, check all your battery connections and the starter amp draw.

Glow Plug Problems

Diesel engines have glow plugs to assist the engine in starting. A relay and timer supplies voltage to the plugs for the number of seconds it needs and then the relay turns off the voltage and the engine cranks. Relays may stick and continue supplying voltage instead of turning off and this will cause your glow plugs to burn out. This is much more noticeable in cold weather when you need the warmth of the glow plugs to crank your engine. Check your glow plugs with a multimeter for their resistance or continuity. If you have excessive resistance or no continuity, the glow plug is bad and needs replacing. You can also test to see if the glow plug module is supplying power to the plugs with a voltmeter to check each plug for the correct voltage when the ignition is turned on. If the glow plug module or relay doesn’t keep the plugs on long enough, your engine won’t start. Most diesel generator controllers will let you change the preheating time and in the winter you should increase it.

Bad Diesel Fuel

In cold weather, bad diesel fuel is when it forms wax in the summer grade 2 diesel fuel and it can plug up the water and fuel separator to block the diesel altogether. Put the generator in a warmer area inside so it can thaw out and replace the water and fuel separator. Then you need to add a fuel conditioner additive to the fuel tank if this is approved by your specific manufacturer. Otherwise, drain the fuel tank and fill it with grade 1 diesel fuel for the winter. If the fuel filter or water and fuel separator is iced over, it is an indication that there is water in the bottom of the fuel tank. In this case, you need to drain the tank to get rid of the water, use summer fuel and replace the filter or the water and fuel separator so the fuel can travel down the fuel lines and to the diesel engine for it to start.

Fuel Injector Pump

Most larger industrial generators use a solenoid or a motor and cable to open a fuel valve and close it. If the fuel valve doesn’t open enough, you won’t get fuel to the engine for it to start. When you turn the ignition on you should be able to hear a click noise inside the fuel pump. If there is no click noise, then the solenoid or the pump or both are faulty and need replacing.

Following this troubleshooting guide should help you to get your used generators for sale up and running.