Yanmar - Cannot Bleed, Will Not Run

[Tspringer]

I have finished putting my Yanmar 4JH2HTE back together after taking everything bolted to it off, cleaning off all the exterior rust and painting everything. The engine room and bilge now look like new... or at least they did.

I have also installed a Filter Boss Commander dual filter and pump system.

I did not remove the injection pump from the engine but I did remove the engine fuel filter and all the injection pump hard lines. Everything was carefully masked and cleaned and then reassembled.

The Filter Boss has an electric pump, as per its instructions I have that pump running and I have been attempting to bleed the injection system as per the Yanmar manual.

Its impossible. No matter what I do, no fuel will come out the hard lines at the injectors. Not a drop. No air that I can tell either.... loosen the nut, nada. Plenty of fuel pours out when the fuel attachment at the injection pump from the engine filter is loosened and plenty of fuel squirts everywhere when the return line at the engine filter is bleed.... so it would appear that fuel is flowing through the injection pump but it is not going down or through the hard lines to the injectors.

This is maddening! I have gone through 3 rolls of paper towels and what seems like gallons of diesel. The entire boat reaks of it now and my once like new bilge is again a diesel stinking mess. Everything has seen diesel at this point.... except the injectors.

What gives? The engine ran like a top before tackling this project. I am at the point of having to call a mechanic as I am out of ideas.



Terry

[Badsanta]

The fuel pump will not be able to push fuel through the high pressure injector pump. Loosen the nut at the injector and crank the engine over. Be sure not to crank to much or you can back fill the engine with sea water from a flooded exhaust. The only way fuel can get through is have it pumped through by cranking the engine.

[Tspringer]

I will try that....

But, it seems fuel is being pushed through the high pressure pump since I can bleed the fuel system at the fuel return on the engine fuel filter top where the line FROM the high pressure pump runs. My understanding was that this was for fuel left over after having fed pressure to the injectors?

The Yanmar manual says nothing about turning over the engine. Not surprising that this would be required though. After all, what can you really expect from a manufacturer who designs something in such a manner that it not only requires manual fuel bleeding but that the means of doing this ensures that the engine and bilge of the boat it is installed in is guaranteed to get soaked in diesel fuel. I really am jaw dropping amazed at how crazy piss poor this stuff is engineered.



Terry

[sailorboy1]

My Yanmar manual says to loosen the lines at the injector and crank the engine.

[Tellie]

BadSanta is right, you gotta crank the engine Terry to bleed the air. If you're doing this yourself, one of those remote push button starters are worth their weight in gold. A few bucks at an Auto store.

[Tspringer]

Bingo!

I do have a remote start and stop buttons in the engine room.... good thing too because the engine stop button on the main panel is not working for some reason, and the alternator is not charging but she DOES run.

In fact, as soon as I cracked the first injector while turning it over it fired. I quickly bled each injector, only the briefest crack open and close of the line was required and she runs great now. THANK YOU!

My Yanmar manual says nothing at all about opening injector lines while turning the engine over. Nada.


Terry

[Tellie]

Originally Posted by Tspringer

Bingo!

I do have a remote start and stop buttons in the engine room.... good thing too because the engine stop button on the main panel is not working for some reason, and the alternator is not charging but she DOES run.

In fact, as soon as I cracked the first injector while turning it over it fired. I quickly bled each injector, only the briefest crack open and close of the line was required and she runs great now. THANK YOU!

My Yanmar manual says nothing at all about opening injector lines while turning the engine over. Nada.


Terry

Congrats Terry.

It's gonna make cleaning up a lot happeir event now that she's running sweetly.

[Badsanta]

click that little thankyou button. But glad to help

[delmarrey]

Yeah! Yanmar says to loosen this screw 2-3 turns, then run the manual pump until there's a solid stream of fuel. But this must only apply when one has changed the filter. BTW Mine has a little nipple to attach a hose to so it doesn't pump fuel onto the motor.

Although, they do give one the impression that

Originally Posted by Yanmar Manual

Bleeding must be done if any fuel system maintenance has been performed (replacement of fuel filter, etc.) or if the engine does not start after several attempts.

I would now think that the manual pump doesn't have enough pressure to continue up to the injectors or that maybe the injector nuts were not quite loose enough for a low pressure system.

[Ex-Calif]

Originally Posted by Tspringer

My Yanmar manual says nothing at all about opening injector lines while turning the engine over. Nada.


Terry

Your (owners?) manual probably is assuming you just did a filter maintenance. In that case the fuel system is full of fuel except for the air bubble you let in.

After an overhaul of the pumps lines and injectors there is no fuel in the system.

Our SOP is to crack an injector and crank the engine ever since we tried bleeding with the manual lift pump.

I hope you get the diesel smell out. I spilled a jug in the back of my car. After soaping and scrubbing and soaping and scrubbing I gave up. A friend suggested charcoal. We got some very porous charcoal (yes just like for BBQing) and left it in the trunk. It absorbed the last of the smell in a week or so.

[GordMay]

Bleeding Air from Yanmar Engine Help
➥ BLEEDING AIR

Excerpted from the Yanmar Service Bulletin
➥ http://www.ldmarineservice.com/files...ulletins.pdf#3

“Bleeding the Fuel System”
1. Make sure fuel tank off is in "on" position.
2. Bleed the air from fuel filter. Loosen the air bleed screw at the top of the fuel filter body and
operate the manual handle the lift pump until the air bubbles completely expel in the fuel flowing
from the filter.
3. Bleed the air from the fuel return pipe. Loosen the connector bolt of the fuel return pipe installed on the fuel injector, and bleed the air by operating the manual handle of the lift pump. (If there is more than one injector, bleed the one at the end of the line).
4. Bleeding the air from the fuel line - (line from the filter to the injector pump). Loosen the air
venting screw at the injection pump and operate the manual handle of the lift pump until an the
air bubbles are out.
5. Bleed the air from the fuel injector. Loosen the nipple on the fuel injector side, set the throttle to half and the decompression lever to the decompression position and crank engine. When no
more bubbles appear in the fuel flowing from the end of the injection pipe, re-tighten the nipple.

[Joli]

Yanmars require you crack everything from the injectors back. Break the compression and roll the engine over to prime the entire system and "don't forget to close the engine seacock" otherwise you might fill the head with seawater via the exhaust valves". Close the system from the fuel tank to the injectors as fuel comes out.

As racers we often were a bit light on fuel . I learned to bleed systems in 5 minutes.

[Badsanta]

The engine lift pump and the manual lever on the bottom or if installed an electric fuel pump will at most supply a few psi The injector pump raises the fuel pressure to 1000 psi you cannot manually pump fuel through the injector pump. You have to open the nuts on the injectors and turn the engine to bleed the lines. If you get any air in the line, air will compress and will not be able to open the pop valve on the injectors and fuel will not flow. You cant just crank it over and expect the air to be pushed through. you have to bleed it.

Please follow the steps provided by Gord May

[GordMay]

Originally Posted by Joli

Yanmars require you crack everything from the injectors back...

Bleed from the filtre(s) forward (in the direction of fuel flow).

[Joli]

Gord! You left out the salient point of my response. No, not the one about always running out of fuel.

Originally Posted by Joli

Yanmars require you crack everything from the injectors back. Break the compression and roll the engine over to prime the entire system and "don't forget to close the engine seacock" otherwise you might fill the head with seawater via the exhaust valves". Close the system from the fuel tank to the injectors as fuel comes out.

As racers we often were a bit light on fuel . I learned to bleed systems in 5 minutes.