changing secondary fuel filter yanmar 4lha

[keith c]

Having no problem changing fuel filter on primary racor fuel filter. Am I correct, is the racor the primary? I have not changed the secondary fuel filter, the one attached to the motor. Could I get info on the bleeding process and location of manuel pump etc. Do I bleed it at the pressure pump the injectors or both.

 

[sunchaser]

Having no problem changing fuel filter on primary racor fuel filter. Am I correct, is the racor the primary? I have not changed the secondary fuel filter, the one attached to the motor. Could I get info on the bleeding process and location of manuel pump etc. Do I bleed it at the pressure pump the injectors or both.

KC
What engine and vintage? What does on engine filter look like, upside down, spin on or ?? Generally, you should not have to bleed. Just be sure the new filter gets filled (several ways to do this) with fuel before you start it - again, engine dependent.

 

[AKDoug]

I run a 4jh, and only change the primary (Racor) every other year and the engine mounted filter twice in six years. They are both one micron filters, so theoretically nothing should get through to the engine mounted filter.

With a one gallon per hour max fuel burn, and clean fuel tank, it's unlikely it would plug enough to limit fuel flow. The Racor change won't require bleeding the line, the pump mounted on the filter will restore the fuel line. The secondary will require you to bleed the line, it's super easy and as I recall the pump on the Racor will purge the line.

You just need to open the bleeder on top of the engine and pump the Racor until the air is bled out.

 

[Cigatoo]

The 4lha has a priming pump on the stbd side (down low on the engine block) under the engine mounted fuel filter. It might have a round plastic cover over the pump handle. Remove the cover, unscrew the pump knob and the pump will expand. Then pump to prime. Just loosen the screw on top of the filter housing to prime. No need to loosen injectors or anything at the infection pump. You should be able to change both the Raycor and engine filter and then prime / bleed both filters by just unloosing the screw on top of the filter and pumping the Yanmar prime pump.

 

[sndbowen]

My secondary filter is mounted with a bolt going thru the bottom of the filter bowl up to the top of the filter. I can’t see how I could fill the filter before th bolt is tightens. The manual says the filter is self bleeding.

I’ve pumped the primer pump many times, but the engine will not fire.

Help!

 

[sunchaser]

SND

What engine?
Do you have experience bleeding this engine?
Does the fuel pump have a lever on it?
Are there any other bolt heads on top the filter housing?

 

[Ski in NC]

Should be a vent screw on top of filter housing. 10mm hex head, I think on the center bolt. Memory foggy. Loosen screw and then pump the primer on the injection pump. Bubbly fuel should eventually come out, pump some more til liquid fuel with no air comes out. Keep a bowl under filter to catch the mess. Then snug vent screw and pump maybe 20 more times, or until primer gets hard to push.

Then try a start. You may need to loosen injector lines at injectors and crank, but never had to do that on this series engine.

 

[sndbowen]

Yanmar 6ly3-utp
No bolts other than those connecting hoses.
This is my first time changing and bleeding the secondary filter.

 

[Ski in NC]

Post a pic of top of filter housing.

 

[sndbowen]

There are no bleeding screws on top. Specs say there is an internal bleeding. It is probably the little fitting at tha center of the lid which has a small hose attached.

 

[sndbowen]

Struggling to post a pic.

 

[sndbowen]

Pic

 

[Ski in NC]

If there is a small hose coming off center bolt as well as a big hose, then that is probably the bleed line. So yes, no need to search for a bleed screw.

Keep pumping, it has to fill the whole canister.

You can loosen the bolt on the center little line and when fuel starts coming out, you know it is mostly filled. Snug it up and pump 20 more times.

 

[Ski in NC]

Looking at the pic, you can loosen the bronze fitting on the hose to the right to tell you when filter is full.

 

[sndbowen]

Any idea how much fuel the plunger pumps? I’ve pump it well over 400 times.

 

[Cigatoo]

I can’t speak for the 6LY but i could fill the Raycor and engine mounted filter on the 4LH in a couple of dozen pumps Or less.
Back to basics. Start from the beginning Fuel is turned on? Not sucking air some place? You removed the old rubber o rings before installing new ones on the Raycor?

 

[DavidM]

That pump you are manually operating is driven from a camshaft in the engine. If the camshaft has come to a rest in the high position, little fuel will be pumped manually. Turn the engine over either by hand with a wrench or with a quick hit on the starter to drop the cam shaft. It should then pump with a longer stroke and lots more fuel.

David

 

[Ski in NC]

Dave I think the LY primer pump is separate from the plunger pump driven off the inj pump cam. So the high cam spot condition does not apply. Not 100% on the 6LY3, might be different.

To the OP, take the sec filter bowl back off and see if it has been filling with fuel. Put a catch bowl under it and pump primer. Fuel should spit out of filter head and dribble into catch bowl.

Did you change the racor at the same time? If so it might be full of air. Primer pump does not like to suck on air.

And make sure you got all the valves in the right lineup!!!

 

[Bacchus]

Looking at the pic, you can loosen the bronze fitting on the hose to the right to tell you when filter is full.

On the 6LYA the center hose connection is the bleeder - guessing the 4 is similar. Just pump until you get steady flow of fuel and then lock the hose connection screw down.

Any idea how much fuel the plunger pumps? I’ve pump it well over 400 times.

Are you unlocking the priming pump? The plunger knob is serrated if I remember correctly and has to be unlocked by turning the knob CCW.
Don't forget to push down & relock CW when done

Here's a pic of the 6LYA set up.

 

[sndbowen]

Yes, I actually ran the engine after doing the racor filter. I try to make sure I only have one thing to test at a time.

As for sucking air not sure where it would be. Only removed the drain plug and the bolt to remove the canister on the yanmar filter. When pumping the priming pump the needle on vac gauge on the racor moves a little which makes me think it’s pumping. Also feels like it’s pumping.
Yesterday after pumping for awhile I opened the drain and it leaked fuel.

 

[sndbowen]

On the 6LYA the center hose connection is the bleeder - guessing the 4 is similar. Just pump until you get steady flow of fuel and then lock the hose connection screw down.



Are you unlocking the priming pump? The plunger knob is serrated if I remember correctly and has to be unlocked by turning the knob CCW.
Don't forget to push down & relock CW when done

Here's a pic of the 6LYA set up.

The images are to blurred to see, but the narrative is what I’m doing with the exception of the bleed screw which is attached to the hose on top in the center of the lid.

The pump is threaded and seems to be working.

 

[Ski in NC]

Go back to post #18 and do 2nd and 4th steps.

 

[sndbowen]

Success!

I loosened the center bolt at the bottom until it weep fuel and then tuned a little extra. This broke the seal at the top of the canister so when I pumped a little more fuel leaked around the top of the canister, tightened the bolt, pumped a few more times and turned the key.?

Thanks to everyone that helped. This is why I love this forum!!!