Mep-003a wont stay running

[orionfuchs]

Hi All

My new to me mep003a will start and run but as soon as I put the switch in the start position it turns off. It has oil pressure. I removed the fuel shut off solenoid and it will stay running but wants to over rev. I checked the governor linkage and it's free. I loosen the throttle cable and it still over revs unless I manually keep it from doing so. The governor seems to pushing higher and I don't know why. Are the 2 problems related? Any help would be greatly appreciated.

 

[Chainbreaker]

Hi All

My new to me mep003a will start and run but as soon as I put the switch in the start position it turns off.
It has oil pressure. I removed the fuel shut off solenoid and it will stay running but wants to over rev. I checked the governor linkage and it's free. I loosen the throttle cable and it still over revs unless I manually keep it from doing so. The governor seems to pushing higher and I don't know why. Are the 2 problems related? Any help would be greatly appreciated.

How long have you had this genset? Where did you procure it from Gov't Auction or Private Sale and any history on it that you are aware of?

If you have not done so already... the Technical Manuals, are located in the banner up top under "TM". Just find the MEP-002 TM's & download.

Just to clarify... Do you mean when you "let go of the Start Switch" after starting it dies? How long are you holding it in the start position, you need to hold it in START for 15 seconds or so until the engine builds Oil Pressure. The Pressure Sensor is one of 2 safeties (Oil Pressure sensor & Temperature sensor) designed to not allow an engine to keep running if the oil pressure drops below a certain low PSI threshold or engine is over a High Temp threshold. What is your actual "oil pressure running" just before you let go of the START SWITCH? Are you using the Starting Procedure on the Placard on right side of Control Box?

It's somewhat common for the Oil Pressure Sensor (located low left of Oil Filter) to go bad and that would not allow it to keep running after you let go of the Start Switch. To Test if the OPS is bad, you could jumper across the 2 terminals temporarily to see if it keeps running. If so, you know it's a bad sensor but do not run it that way more than a few seconds to test the switch just in case it were to be an actual low oil pressure situation (Verify pressure on OP gauge that its at least ~30 PSI).

You SHOULD NOT REMOVE The fuel shutoff solenoid. There is a procedure for setting the governor RPM setpoint in the TM's.

 

[Chainbreaker]

Also read through this thread below, it has lots of good information on checking out your genset.

Generator Libby MEP-003A | SteelSoldiers

 

[Ray70]

How did you loosen the throttle cable, is the black knob all the way in and it still revs over 60hz? ( I assume you're judging the speed by the Hz meter?)
How high is it with the throttle cable loose? and with the cable loose are you sure the lever under the blower shroud is loosening up on the governor spring and not frozen?
Also, where is the governor spring in relation to the bottom of it's adjustment thread ( look for the star wheel where the end of the spring hooks on, to the right of the fuel solenoid under the blower wheel cove,. You want to be about 3-4 turns up from the bottom ( refer to the governor droop adjustment procedure in the TM )

 

[orionfuchs]

I bought it from a government auction a week ago. I have no history on it at all. It looks to be in good shape but definitely been sitting for years. The diesel smelled horrible and the plunger on the injector pump was stuck. After a few hours of draining fuel and messing with the injector pump i got it to run. I'll try jumping the ops. The oil pressure is around 40 when I let off the starter. I do have multiple manuals for it and have looked at the trouble shooting sections. I loosened the throttle cable up all the way by the adjustment nuts beside the governor. The spring on governor was a few grooves up from the bottom. Just to make sure it wasn't pulling to hard on it I put the spring all the way to see if that would help. It didn't. For what ever reason the governor just pushes it to full throttle.

 

[Guyfang]

Put the set back together like it was.

Then place a jumper wire on TB5-8 to TB5-9 in the control box. Start the set up. Will it run? If so, take the jumper off, and then remove one wire from S5, (the oil pressure switch) and hook it to the other wire on S5. Will it work? Yes, then the S5 is bad. If not, hook the S5 back up and jump the S4, (Temp switch). Start it up, and see if it will run. tell us what happens.

 

[orionfuchs]

I just had time to mess with it again. The ops is bad. Jumping around the sensor will keep it from turning off. Now, my next issue is the governor. Even with the throttle cable loose, no tension at all, it wants to rev up. I moved the spring on the governor arm all the way to bottom also. I haven't found anywhere in the manual that covers this issue. Any ideas?

 

[orionfuchs]

Also I did get more info on it. There was an envelope that had repair/maintenance. It goes back to 2014. Nothing major since then anyways. The Oregon national guard couldn't get it to run the last 2 times they tried, in 2020 and 2023. They did show it run and was load tested in 2017. In 2014 it had 1.2hrs and now it has 3.8hrs

 

[Guyfang]

I just had time to mess with it again. The ops is bad. Jumping around the sensor will keep it from turning off. Now, my next issue is the governor. Even with the throttle cable loose, no tension at all, it wants to rev up. I moved the spring on the governor arm all the way to bottom also. I haven't found anywhere in the manual that covers this issue. Any ideas?

The -34 tells you how to make the basic adjustments/install a new K5, (Governor Solenoid) Make sure what you see in the TM is what you have on the set. Then try it. Also, test the K5 IAW the -34 TM.

 

[Ray70]

Seeing the you had issues with the throttle lever being stuck, I'm wondering if you either still have a sticky throttle control lever ( unit ) or there is also a good chance the plunger guide inside the injection pump has skipped due to the sticky linkage and presumably a sticky plunger inside the pump.
2 things to check, is the machine difficult to start, does it crank excessively long before firing up? and 2nd. If you keep the engine speed around 60hz by hand, do the valve covers get excessively hot within like 5 minutes or less? These are 2 clear indications you plunger guide has skipped and injection timing is 90 or 180 degrees off. However, I've never had a broken plunger guide cause uncontrollable throttle speed.

put the governor spring back on the 4th coil up from the star wheel and put the solenoid back on.
Take a picture of the governor linkage arm where the "forked" adjustment slot is where the arm meets the linkage going down to the pump so I can see where the adjustment is and how high the arm is in relation to the top surface of the solenoid.
Also send some pictures of the lever arm inside the blower wheel cover where the cable and the spring are attached. A lot can be learned from the angle of that lever in relation to the centerline of the engine. It should be pretty close to 90* from the engine block.

Your problem could be a simple as a bent governor linkage arm or as difficult as a malfunctioning governor flyball assembly.

Lastly a video of what the linkage is doing while running would also help.

 

[Ray70]

Something else to note, the governor assembly itself does not have any ability to increase throttle ( or increase engine speed )
The spring is always trying to pull the linkage up, giving the engine full throttle.
The only action the governor can take is to push back harder and harder against the spring as engine speed increases to try to keep the engine speed under control.
Eventually they reach an equilibrium where both the spring and governor are pushing and pulling equally, that becomes your set engine speed and you change this set point by pulling on or loosening the cable which increases or decreases spring tension slightly to vary the point where the spring and governor weights are both equal.
So when the engine is off the spring pulls the throttle wide open, but because the vertical linkage arm is spring loaded, the fuel solenoid is able to extend the spring loaded portion of the linkage, pushing the lever on the IP down, cutting off fuel flow even though the spring is still trying to give it full throttle.
When you turn the switch and crank the engine, the solenoid retracts, allowing the IP's throttle arm to go to wide open throttle, the engine starts at W.O.T and as soon as the governor weights begin to spin the flyball cage expands, pushing on the lever and attempts to bring the engine speed down to the set point.
So you should see the linkage go up to full throttle then quickly come back down some. or if you manually push up on the linkage while its running, the governor weights should push back against you.
If neither of those 2 things are happening and the engine truely is at W.O.T constantly, then there is most likely something stuck or broken within the governor assembly under the timing gear cover. If the governor does push back against you, then the problem is most likely linkage related.

 

[orionfuchs]

I'll try to look at it this evening and get pics and video. Is the fuel shut off solenoid the same as the governor solenoid? What is the electrical thing on the front side of the governor that has point looking things inside? Also to my knowledge, the throttle linkage hasn't been stuck. When I said I loosened it, I mean that I took the adjuster part of the cable out of the holder to take all the tension off the cable. Just to make sure it wasn't pulling on the arm.

The center plunger on the injector pump was keeping it from running initially. When I took it apart and cleaned it, the needle valve inside was stuck. I did get it unstuck and put it all back together and was able to get fuel through to the injectors and got it running.

 

[Ray70]

Ok, I misunderstood on the lever vs. the delivery valve being frozen.
The governor / Fuel shut off solenoid is the large electronic solenoid that pushes down on the IP lever to shut the machine off.
The other device you're describing sounds like the centrifugal switch the disengages the starter when the machine is running. That is the points device under the tin cover held on by a single wing nut, directly to the right of the throttle lever.

 

[Guyfang]

I would suggest that you open up the -12 and -34 TM's, and get familiar with the components and use the proper nomenclature. This helps keep everyone on the same sheet of paper. For instance, Governor Solenoid. Its K5. Much easier to write.

The other device you're describing sounds like the centrifugal switch the disengages the starter when the machine is running. That is the points device under the tin cover held on by a single wing nut, directly to the right of the throttle lever. This is the S7.
And so on.

 

[orionfuchs]

 

[orionfuchs]

 

[peapvp]

The governor cable needs to sit in the bracket and secured with the nuts
You can adjust the position of knob then by moving the the two nuts
Secure them when you determined correct position
I don’t have the manual on hand at the moment to tell you the exact procedure

 

[orionfuchs]

I've been trying to get a video that will upload but to no avail. It is hard to start and rolls white smoke

 

[orionfuchs]

Definitely seems like the governor isn't doing anything. Once I start cranking, it goes to wot and just stays there

 

[2Pbfeet]

I think that first base is to follow up on @peapvp post to bolt down the throttle cable. It won't do anything productive until you do that. Once it is bolted down, you can start the adjustment process.

After that could you take a picture of the exhaust "smoke", if it still exists? I have found that diesel smoke color is very very helpful for diagnosing problems.

All the best,

2Pbfeet