Bleeding Yanmar 3ym30

[FabioC]

Could somebody give a simple step-by-step explanation of how to bleed a Yanmar 3ym30 to restart it in case it has run out of diesel?

Thank you!

[SFS]

You should really get a copy of the service manual and read it. It will give you the location of the bleed screw, which needs to be opened, and the location of a lever used to "pump" fuel up to and through that bleed screw. Simply pump until you get fuel (rather than bubbles) flowing from around the screw. Then close the screw. A rag should be handy to catch the bled fuel.

[Wotname]

^^ what SFS said +1

Most likely the YM series will be bled in a similar manner to the GM series where there are two bleed screws; the first on the engine mounted fuel filter and the second on the injector pump. These have nylon washers under them and should not be overtightened - they will strip if overtightened.

If you have an off engine fuel filter, that will also have to be bled (first).

[CaptFrankM]

I work for a sailing school that uses boats that have the 3YM30AE engine. I do the maintenance on the boats, including changing fuel filters. I have never had to bleed the engines after changing filters. It is not that I am very careful to prevent any air from getting into the system, it is simply that these engines are "self-bleeding." They run a little rough for the first few minutes, but they quickly get the air worked out and run solidly again.

You CAN bleed them as noted above, but try just restarting it a few times first. Chances are it will catch.

[TheOffice]

On the 3gm the bleed screws are 10mm.

[SFS]

There is only one bleed screw on the YM series.

And as stated above, it is billed as a self bleeding engine. I have not tested that theory, as it is so easy to bleed, but just starting it and letting it run would sure avoid the potential for any (though very minor) mess.

[FabioC]

Thank you all for the advice.
I guess I do not understand much about engines, but what design feature allows an engine to be self-bleeding, as opposed to an engine that is not?
Also, why certain engines are bled from one location, while other engines require to be bled from two locations?
I find all this quite mysterious... can anybody explain?
Thank you!

[Sailmonkey]

Originally Posted by FabioC

Thank you all for the advice.

I guess I do not understand much about engines, but what design feature allows an engine to be self-bleeding, as opposed to an engine that is not?

Also, why certain engines are bled from one location, while other engines require to be bled from two locations?

I find all this quite mysterious... can anybody explain?

Thank you!

A “self bleeding” engine is plastic men’s in such a way that an electric fuel pump is able to circulate fuel from the tank, through the injection pump and back to the tank. They are 99% self bleeding, but there are still scenarios that may require cracking an injection line nut and bleeding after the HP pump.

As far as different bleed requirement for different engines.....that’s easy. They were all designed by different humans. Human 1 may design a complete system that has 1 high point and can be bled from there. Human 2ay decide that their design of pump is superior and it requires bleed ports in 6 different chambers.

[Wotname]

^^ And then along comes human #3 who installs fuel tanks and additional filters in such a way that requires additional bleeding over and above what the other humans have done.