MEP-831A Governor Control Replaced - no start

[zapp]

Hi -

Thanks @kloppk I received the new board and bolt and got it installed - no issues. I just got this unit (18 hours). Haven't got it started yet. I replaced the governor control as everything I have read says high probability of failure, drained old fuel, and replaced with new, and drained water/fuel in filter clear bowl. I also pulled the fuel line to the injector and it is getting good fuel flow coming through.

I started tracing through the TM but was curious how the governor actuator mechanically is supposed to work? I've attached some pictures and a video link of trying to crank it. The arm doesn't move at all. I lift it up and still doesn't fire. Feels like there is something electronically causing it not to fire. Any ideas?

Also, this one had a battery in it with 11V showing, any luck with reconditioning? I'm using two (2) car batteries in series to attempt starting so I have good power.

Video: https://youtube.com/shorts/dyylYeWsrOc?feature=share

 

[kloppk]

I've tried to recondition two Concode batteries. At first, they seemed to recover but both quickly died.
I replaced them with pairs of new 12 V AGM's in both sets. They work great.

I don't see anything wrong in the pictures posted. Minor issue is someone removed the locking factory safety wire from the top adjusting bolt on the mechanical governor. That indicates someone fiddled with it. Once that's sealed at the factory in normally should never be adjusted.

When you lift the actuator arm off the magnet does the black arm the rod pushed down on follow the arm up?

With my GC installed the actuator arm should pop off the magnet as soon as you engage the starter. In the video I see it isn't.
Could be due to a few things.
1) Wiring issue between the GC and the actuator.
2) Actuator plug disconnected
3) Actuator defective
4) Someone has adjusted the magnet strength too high.

Check for continuity from terminals J & H on the GC to the wire harness plug P10 that the actuator connects to.
Check the resistance of the actuator. It should be about 10 ohms.

If all checks out, try this.
Lift the actuator arm off the magnet. Then move S1 from STOP to START. The actuator arm should swing to WOT for a moment and then back down some. Does it do that?

 

[zapp]

Hi -

I did the following checks per above and didn't see any issues.

1/ Checked continuity between J&H and the actual plug to the actuator (had continuity).
2/ Ohm'd actuator from the plug and had 10.1 ohms
3/ Reconnected armature plug and checked continuity and ohms from J&H and both were the same readings.
4/ Tried starting holding actuator arm away from magnet and it did give a slight pull for a split second.
5/ Unplugged the fault module per TM and same thing.

Here is a video where you might be able to see the actuator arm pull when attempting to start:

I'm going to look at fuel I guess now? I'll change fuel filter to make sure nothing going on there but I was getting flow when I pulled fuel line off injector. What's weird is it crank's but I don't get any startup at all...

Should the black arm at the bottom of the armature arm have any travel in it? It only moves slightly up/down (below)

 

[kloppk]

Thx for the reply and video.
So there appears to be two issues.
1) I suspect the magnet strength is set too high not allowing the actuator to lift off the magnet.
Low starting battery voltage could cause this too.
2) Most importantly and why it's not starting is the black arm (throttle) that the rod presses down on did not lift up at all when you lifted the actuator manually off the magnet. The black arm should always be in contact with the spherical nut on the end of the rod. With the black arm stuck in that down position the engine will not start. That down position cuts off fuel from the metering pump to the injector.
In this snapshot from your video you can see the rod lifting up but the black arm is NOT following.



You need to determine why the black arm is not moving up. You should be able to easily raise and lower the black arm.
Mechanically the black arm movement changes the metering pumps fuel flow amount.

On a set I parted out the black arm was stuck and wouldn't move. Turned out the metering pump was seized up preventing the black arm from moving. I hope that's not the issue with your set.

 

[zapp]

Hi - thanks for all the info!! Yes, it doesn't move and feels solid. I'll take a look at pulling it apart tomorrow. I looked in TM-9-6115-639-13 but only see the arm and not what it connects to unless I am missing it. Is there a different name to search for on that piece? I see 4-54 in the TM but no additional detail. Just curious on the one you had, any idea what caused it to lock up?

 

[kloppk]

To see how it fits together you need to look at the engine specific TM 9-2815-257-24P

The black arm is bolted to "P/O 23". P/O 23 is attached to the end of the shaft of 23.
The top of 23 has a "U" shaped cup in the top if it. The metering pumps fuel control pin sits on the "U".
As 23 swings back and forth it adjusts the fuel flow from the metering pump to the injector.

On the one I parted out the metering pump was seized due to corrosion and its pin would not rotate the metering mechanism of the pump causing 23 to be stuck hence from moving hence the black arm not being able to move.

 

[zapp]

I'll dig into that and see what I have in the morning, thanks again!

 

[zapp]

Hi - so I dug into it this morning. Took the governor assembly apart and shaft (P/O 23) would not turn. After looking at the drawing I decided to pull the injector and found the "U" shaped slot at the top for the metering pump was not seated. The metering pump arm was actually off to the side blocking it from physically moving. I rotated the shaft to reset it and got everything turning the way I think it should.. Changed fuel filter, tried to adjust governor per instructions, and hooked up two 12V/series fresh charged batteries. Still no start. I've added a couple pictures below. The only thing I can think of now is whether maybe when I drained the tank there was still water left in, or is there a problem with the injector? It doesn't even try to make a rumble.. I've gone through TM but I must be missing something. I've uploaded some video's from what I found and trying to start. Any ideas are always appreciated! Thanks!

Actuator Arm Locked:

U Shaped component 23: https://youtube.com/shorts/l_e5dqPt1d0

After reconnecting actuator lever link fuel meter:

Still won't start:

 

[kloppk]

That explains why it was stuck! Obviously, someone removed the pump trying to fix an issue and caused another one.
While you had the pump out did you verify you could compress the plunger on the pump to verify it wasn't stuck?
The pumps in 802's and 803's will get gummed up and stick compressed and not pump fuel.

You might want to crack the hard line at the injector and then crank the engine to A) verify the pump is pushing fuel to it and B) purge any air out of the fuel lines.

 

[2Pbfeet]

Hi - so I dug into it this morning. Took the governor assembly apart and shaft (P/O 23) would not turn. After looking at the drawing I decided to pull the injector and found the "U" shaped slot at the top for the metering pump was not seated. The metering pump arm was actually off to the side blocking it from physically moving. I rotated the shaft to reset it and got everything turning the way I think it should.. Changed fuel filter, tried to adjust governor per instructions, and hooked up two 12V/series fresh charged batteries. Still no start. I've added a couple pictures below. The only thing I can think of now is whether maybe when I drained the tank there was still water left in, or is there a problem with the injector? It doesn't even try to make a rumble.. I've gone through TM but I must be missing something. I've uploaded some video's from what I found and trying to start. Any ideas are always appreciated! Thanks!

Actuator Arm Locked:

U Shaped component 23: https://youtube.com/shorts/l_e5dqPt1d0

After reconnecting actuator lever link fuel meter:

Still won't start:

Congratulations on freeing up the control arm. The Yanmar manual warns about damaging the control arm if the pin is not seated in the yoke, but your control arm looks to be in the ball park. With luck, the governor itself is not stuck or damaged.

As @kloppk pointed out above, I will say that this engine is particular about having all of the air out of the high pressure side, so I would start by bleeding the diesel some more at the injector. Then try cranking it.

All the best,

2Pbfeet

 

[zapp]

Thanks I'll give it a try and let you know how it goes. I did it from the fuel filter to the injector and it flowed very well. Will crack hardline on injector and see.

That explains why it was stuck! Obviously, someone removed the pump trying to fix an issue and caused another one.
While you had the pump out did you verify you could compress the plunger on the pump to verify it wasn't stuck?
The pumps in 802's and 803's will get gummed up and stick compressed and not pump fuel.

You might want to crack the hard line at the injector and then crank the engine to A) verify the pump is pushing fuel to it and B) purge any air out of the fuel lines.

Is the pump with the spring on the back of the injector? Just trying to verify where I should apply force to confirm it isn't stuck. Thanks!

 

[kloppk]

This. You want to verify you can press here and compress the spring and it springs back when you let off pressure.
It's a strong spring.

Looking at other pics on the web of the IP yours looks like it might be stuck in the compressed position.

 

[zapp]

This. You want to verify you can press here and compress the spring and it springs back when you let off pressure.
It's a strong spring.

Looking at other pics on the web of the IP yours looks like it might be stuck in the compressed position.

View attachment 939392

Got it, thanks!! Will give it a try and follow up.. Most likely tomorrow, snow coming down and super cold on the way and my wife says I need to be ready for driveway cleaning duty.. Thanks again!

 

[zapp]

So I took the injector pump back out it looks/feels like it is seized in the compressed position. I tried pushing down on it but it is already bottomed out with no travelI either direction. I found a video of a guy rebuilding a similar pump and it looks like the little ball should rotate freely to actuate the plunger. I can't move it at all on mine. I think when I put it back together yesterday I actually moved it from the "left" of the "U" cradle to the "right" which allowed travel on the governor level looking like it was working. I put it back in and made sure it was in the "U" and the governor lever didn't move. I also tried taking the injector apart per the video to see if I could figure out what was going but could not get the spring to compress and slip the retainer clip off.

Any idea where best place to source a new injector pump?

Seized injector pump (can't rotate): https://youtube.com/shorts/yp_YDpEBtSE?feature=share

Tutorial of rebuilding similar injector pump:

 

[2Pbfeet]

Any Yanmar dealer, if you have one in the area. (I think that the part is Yanmar 783350-51701, but be prepared for sticker shock.) $250 on eBay at the moment...

Chinese knockoffs online if you need it now, just make sure it is for the L70 engine. I have bought the ITACO version for L100 and it worked. (Amazon) Just make sure you get the elbow pointing to the correct side with no solenoid.

All the best,

2Pbfeet

 

[kloppk]

I had two seized pumps on an 802. Both stuck in compressed and wouldn't rotate.
Took the tops off both and took out the loose parts.
Soaked it in Carb Cleaner for a few days.
Then used as BRASS drift and a small hammer to drive the plunder back down to the non compressed position.
Soaked some more.
Then started to compress and release the plunger from the spring end to start to free it up.
More soaking.
More compressing and gradually the arm started to rotate too.
With enough cleaner and exercising both pumps came back to life.
Re-installed and the 802 started right up.

 

[zapp]

Thanks, I'll give that a try and see if I can get it loose. It's really tight but maybe break through with some soaking. One thing about this whole process is I now know a lot more about how this thing works! . Still waiting to hear it start but I think I'm getting closer.. Will post updates as I get handle on injector pump. Thanks for all the info!

 

[Light in the Dark]

Definitely soak it for a couple days before firing the greenback pistol at the problem.

 

[DieselAddict]

For sure. I've been able to free up every stuck one I've come across with some patience. I'm into double digits.

 

[zapp]

You guys were spot on!! Couple hours in the carb soak and was able to get the spring off with a little work. Plunger was definitely pushed up and took some light tapping to remove. I put it back in the soak to sit for another hour or so. What about that paper gasket? Reusable or permeated? It doesn't seem torn.