Diesel engine won't start

[Tillsbury]

Don’t forget to have the seacock shut while you’re doing all this cranking again and again otherwise the exhaust will fill up with seawater and life will go bad quickly... open the seacock the moment the engine fires up.

[Lepke]

A diesel fires when the air in the cylinder is compressed enough to reach about 500°F. Then the fuel is sprayed under high pressure. If there is any air in the injector tubes it compresses and causes the fuel pressure to go below what it takes to open the injector.
If the engine is at a higher temperature before starting it's easier to reach 500°. So things like a block or pan heater can make a balky engine fire. Even a hair dryer in the intake helps.

If the engine is turning too slow, some of the compression leaks past the rings and the engine doesn't reach 500°.
If the engine was running before the fuel filter change, I think it's an air in the fuel problem.

[Snore]

Originally Posted by Siberian Sea

I would give it a shot of starter fluid in the air intake and see if it would fire with that.

EVERY mechanic I know, recommends NOT doing this.

[a64pilot]

Originally Posted by Snore

EVERY mechanic I know, recommends NOT doing this.

If you do it right, it won’t cause problems, many, many farm tractors in days past came from the factory with an ether can attached to a solenoid, press a button and ether was injected.

To do it right, first you must be absolutely sure your glow plugs are disabled, if one is hot then the ether can ignite regardless of piston position and this can cause damage.
Then only shoot a short shot of ether when the engine is turning over, do not shoot a big shot, then hit the starter.
It usually takes two people to use ether, one to operate the ether, and a second to start the engine.

Problem is many don’t know how to use ether and if you don’t, then you can damage the engine.

[Perna]

+1 for starter fluid just to get it going

Good luck.

[mowerandy]

Yeah - I used to scorn those who carried starter fluid (ether spray), but now I do too as it can be quite useful diagnostically, as well as for getting tired motors running...
If your motor cranks up and then dies after a spray (ie will not keep running even if you keep spraying) then go straight to your exhaust system...
I put a cordless blower on the engine end of the system and make sure it blows through without significant resistance. If it does then take a good close look inside your cylinder head exhaust journals -use compressed air and or a wire to see if you are all coked up in there - this was our problem, and it took ages to finally uncover the cause, as the head looked great from all angles.

[Cpt Mark]

Forget ether on Diesel engines. WD40 sprayed into the air intake as you're cranking will do just as well and when the engine starts to run out of fuel, give it another shot. Easy, cheap and you probably have some on board already.