How to Prime a Diesel Generator – Complete Guide

Priming your diesel engine is a critical process to keep the engine, fuel lines, and filters free from air. Most of the latest models come with a primer, but older models may not have a primer with them, it is also possible that the primer pump may stop working. Instead of replacing the primer pump and spending a hefty amount of money on it, you can prime your diesel generator yourself.

Note: Priming of the diesel engine is ONLY to be done with diesel and not any other type of generator.

In this article, we will walk you through all the steps for priming your diesel generator.

Necessary Equipments

  • Mechanic repair manual of the engine
  • Wrench and screwdrivers
  • Diesel (fresh)
  • Fuel filters
  • Priming Pump (any suction device with a tube for connection, you can also use an oil suction kit)

Steps to Follow to prime a diesel generator with Priming Pump

Step 1: Go through the repair manual to get familiar with your machine. A repair manual usually comes along the generator; you can also find it online easily.

Step 2: Now open the fuel supply valve. It will allow diesel to flow through the system, reach all the filters and other parts of the engine.

Step 3: The real action begins now. Start with the fuel filter, open the bleeding plug, and let all the air and diesel flow out from it. Now connect the suction machine and let the bubbles and diesel be sucked away. Please keep in mind that this is not a onetime thing, you will have to do it many times if you are using a manual suction machine. If it is electronic, the time taken will depend on its power and amount of air in your generator.

Step 4: Repeat the same process for all the filters. Make sure that you do not leave any air behind. Look out for damaged filters and replace them now. Once you are done with this filter, mark it so that you do not get confused later on.

Step 5: After working with all the filters, now add fresh diesel in the tank. Start your generator, it may be a bit cranky at first, but once all the air is out, it will run smoothly.

Priming a diesel generator without priming pump


Priming a diesel generator is not an easy task. It may seem like so, but it takes time, patience, and technical knowledge. Priming is important to ensure a longer engine life and proper output.

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