How to Prime a Diesel Engine

01. 08, 2022

Prime a diesel engine is the process of filling the engine with working fluid ( diesel) and removing the contaminants present in the diesel.

To Start a Diesel When it Runs Out of Fuel, if a diesel-powered truck runs out of fuel, the easiest way to start with no air in the fuel line is to just get some diesel and put it in the tank, which will restart the truck. However, if you have to do some work on the fuel system, that's not going to happen. If the fuel lines are full of air, the diesel will not pull fuel from the tank to the engine and when this flow is interrupted by air bubbles, a symptom known as "air lock" occurs, causing the engine to shut down and refuse to start, so you must first fill the engine fully with fuel before attempting a successful restart. Fill the engine fully with fuel before attempting a successful restart.

Diesel Engine| FAWDE

Diesel Engine| FAWDE

What you will need

Mechanical repair manual for the engine

Spanner and screwdriver

Diesel engine

Fuel filter

Start the handle pump

Steps of Prime a Diesel Engine

Step 1

Find the operating manual for your product to provide you with all the specific details of your diesel engine. Look in the engine manual for the location of the fuel starter pump and bleed screw. The pump and screw will normally be located somewhere near the engine fuel filter. The starter pump will be a large button, rubber ball or small lever.

How to Prime a Diesel Engine position of bleeder screw

position of bleeder screw

Step 2

Carefully inspect the fuel system and check for any obvious air leaks. Fill with clean fuel to perform this operation.

Step 3

Loosen the bleeder screw a few turns. The loose bleed screw allows air to leave the fuel line as the fuel is pulled from the fuel tank to the fuel filter.


Pump the starter pump until the diesel fuel flows out of the loose bleed screw. The starter pump is very small and your fuel line may contain a lot of air, so be prepared to pump for 5 to 10 minutes before you see fuel flowing out of the bleed screw.

Step 5

Tighten the bleed screw with a screwdriver. Try to start the engine normally. You may need to start the engine for 10 to 15 seconds before it starts and runs. If the engine does not start within 15 seconds of starting, repeat the filling process to get more fuel into the fuel filter and pump.

workers to Prime a Diesel Engine

workers of diesel engine 

If you have a need for a diesel engine or have any questions about diesel engines, FAWDE, as a manufacturer of diesel engines, will provide you with quality products and answers!

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