How to Start Cummins Engine Under Cold Weather

It is very important to know how to correctly start Cummins engine. In this way It not only helps prolong the engine’s service life and also keeps the generator set run smoothly.

Cold Weather Starting

Note: A water jacket heater is recommended for stand-by generator set applications installed in a cold climate.


The glow plug system supplies heat to the cylinders so that compression temperatures are sufficient to ignite the fuel.

To aid in starting the genset engine when the temperature is 50 °F(10.0°C) or below, an intake air preheater is available. Preheater equipment consists of a hand-priming pump to pump fuel into the intake manifold, and a switch to turn on the glow plug which is electrically heated by the battery. Fuel burns in the intake manifold and heats the intake air.

Warning: Do not use vapor in conjunction with the preheater. To do so could result in a fire.

Steps to use the preheater for cold starting:

1. Set the throttle in idle position. Turn the glow plug toggle switch to the “NO” position. The red indicator light must be on.

2. After the red light has been on for 20 seconds, start cranking the engine. As soon as the engine begins rotating, operate the preheater priming pump to maintain 80 to 100 psi (552 to 693kPa) fuel pressure. Use of the primer before the 20 seconds interval will wet the glow plug and prevent heating.

3. If the engine does nor start within 30 seconds, stop cranking. Wait one or two minutes and repeat the cranking operation.

4. After the engine starts, pump the primer slowly to keep the engine idling smoothly. In cold weather this may require 4 to 5 minutes or longer. Do not accelerate the engine.

5. When the engine has warmed up so it does not falter between primer strokes, stop pumping. Close and lock the primer. Turn off the glow plug toggle switch. (The red indicator light will go out.)

6. If the engine gives no indication of starting during the first three full strokes of the preheater pump, touch –check the intake manifold for heat. If there is no heat, check the electrical wiring. If the wiring is all right, remove the intake manifold and check the preheater.

Note: The preheater priming pump, switches and resistor are located at the instrument panel and should be checked during engine starting.

The cold starting aid, approved for use in Cummins Engines, has been based upon starting aid capabilities to -25°F(-32°C).

Cautions: Do not attempt to use vapor compound type starting aids near heat, open flame or on engines equipped with a glow plug system.

Recommended Starting Technique Using Fleetguard Starting Aid

1. Set the throttle for idle.

2. Disengage the driven unit or make sure gears are in neutral.

3. Open the manual fuel shut-down valve, or electric shut-down valve, whichever is used.

4. Engage the starter and while cranking, apply metered amounts of starting fluid until the engine idles smoothly.

Use of Starting Fluid Without Metering Equipment

1. Spray starting fluid into the air cleaner intake, while a second man cranks the engine

Warning: Never handle starting fluid near an open flame. Never use it with a preheater or flame thrower equipment. Do not breathe the fumes. Use of of too much will cause excessively high pressures and detonation, or over speed the engine.

2.Starting aid fumes will be drawn into the air intake manifold and the cold engines should start without difficulty.

Warning: Fuel oil or volatile fuel cold starting aids are not to be used in underground mine or tunnel operations. If the engine is so equipped check with the local U.S. Bureau of Mines Inspector for use of the starting aid.

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