Questions about MEP-002A

[Boonies]

I bought an MEP-002A in 2013. I recently bought another and there are some differences that I wanted to ask about.
1) The oil pressure gauge on the new one does a weird thing. It reads about 40PSI when the generator is running. When I stop the generator it will stay up above 40 for somewhere around 5 minutes and then drop to about 10. If I leave and come back later it will be at 0. The older generator goes to 0 pretty quickly when it stops. Do you think it is a problem in the engine or the gauge on the newer generator?
2) The newer one will occasionally stop due to the thermal cut-out switch. It has done it I think 5 times in the last 600 hours of run time. The older one has only done that once in the last 9 years. They are both powering the same loads. Could the switch be faulty, is there an easy way to check that?
3) When I stop the newer one with no load on it, it will wind down more slowly (Maybe 7 to 10 seconds before it completely stops spinning) The older one will stop spinning fairly quickly (About 3 seconds or so) I know diesel engine have a high compression ratio. Do think there is a compression issue in the newer generator? It runs well and can supply a load varying between about 4 and 5kW for hours with no problem (Except the overheating mentioned above).
4) They both use oil. It doesn't seem like either of them are burning oil and there are no leaks. They both vary but the older one is somewhere around 1 quart every 70 to 80 hours of run time. The newer one is around 1 quart every 50 hours. Does this seem normal (OK) for these generators?
Thank You

 

[rickf]

Sounds like you have a partially plugged up oil pressure gauge. The thermal shutdown is most likely caused by the flaps not opening in the shroud, or critter nests in cooling system of the engine. This needs to be checked ASAP since overheating an air cooled engine is certain death for the engine. Shutdown times should be the same, either compression, load or fuel shutoff are in play here.

 

[Boonies]

Sounds like you have a partially plugged up oil pressure gauge. The thermal shutdown is most likely caused by the flaps not opening in the shroud, or critter nests in cooling system of the engine. This needs to be checked ASAP since overheating an air cooled engine is certain death for the engine. Shutdown times should be the same, either compression, load or fuel shutoff are in play here.

Thanks for tips. I checked the flaps and they appear to be working fine. No critter nests. I did find that the oil cooler radiator was plugged with sludge. I cleaned out the radiator and did a flush on the oil system and put in new filter. It works great now, no overheating. The oil pressure gauge improved, but it still sticks some. I verified that the low oil cutoff switch is working, so I am not concerned about the gauge.
I still don't know what is going on with the shutdown time. The newer generator does take about 3 to 4 times longer to stop spinning. The power output is strong and consistent, so for now I not too worried about it. The newer generator does use a bit more oil which I am not happy with, but it is workable.

 

[Guyfang]

What I would have done with the oil, was this. Before changing it, drain a QT out of the set, dump a QT ATF in it, and let it run a half hour. Then change oil. The ATF will clean out lots of sludge and crap. Different stopping times? Could be a lot of things. Could be a main gen bearing. Could be compression. When you shut it down, does the engine keep running? Or does it shut off and the engine just continues to spin?Because if the engine continues to run, Check the Fuel shut off linkage.

 

[Boonies]

What I would have done with the oil, was this. Before changing it, drain a QT out of the set, dump a QT ATF in it, and let it run a half hour. Then change oil. The ATF will clean out lots of sludge and crap. Different stopping times? Could be a lot of things. Could be a main gen bearing. Could be compression. When you shut it down, does the engine keep running? Or does it shut off and the engine just continues to spin?Because if the engine continues to run, Check the Fuel shut off linkage.

/
Thanks for info. I will do the ATF next oil change. When you say "main gen bearing" is that in the engine or generator rotor? Which end? Is there any way to check it without major disassembly? If it was compression, wouldn't that have a significant impact on running and power output. It runs smooth and strong and I have drawn at least 5kW for probably up to an hour or so, no problem. It does shut off (fuel is cut off) but it continues to spin. It immediately starts to slow down, but takes around 10 seconds to completely stop.

 

[loosegravel]

/
Thanks for info. I will do the ATF next oil change. When you say "main gen bearing" is that in the engine or generator rotor? Which end? Is there any way to check it without major disassembly? If it was compression, wouldn't that have a significant impact on running and power output. It runs smooth and strong and I have drawn at least 5kW for probably up to an hour or so, no problem. It does shut off (fuel is cut off) but it continues to spin. It immediately starts to slow down, but takes around 10 seconds to completely stop.

Sometimes the shut down solenoid simply reacts slower than normal. I would watch it when you shut down the machine with main switch S1. See if it reacts slowly. Or, simply shut down the unit manually by pulling the lever toward shut down by hand. See if the engine shuts down normally that way. I had an MEP-803A which uses the same shut down solenoid and governor control. It took about 5-7 seconds to shut down. It was simply a lazy solenoid or linkage. I didn’t think any more about it.

 

[Guyfang]

Main gen is the generator assembly, or as often refereed to as the Main A.C. The bearing is at the rear of the set. You can get at it, but its a bit of a PITA, if you have never done it before. Why don't you make a video of shut down. Maybe shot the fuel shut off linkage. That way we can see and hear it during shutdown.

 

[Chainbreaker]

....
2) The newer one will occasionally stop due to the thermal cut-out switch. It has done it I think 5 times in the last 600 hours of run time. The older one has only done that once in the last 9 years. They are both powering the same loads. Could the switch be faulty, is there an easy way to check that?

Just a FYI... there are "2 conditions" that will cause a safety shut down of the engine... a thermal condition via the thermal switch AND low oil pressure sensing via the oil pressure sensor switch. There is a chance of a faulty oil pressure sensor switch going bad or being partially plugged & not sensing oil pressure correctly causing shutdowns.

I just went through several random shutdowns that increased to the point of stopping the engine as soon as I let go of the start switch on one of my -002a's a few months ago. Since I already had a spare thermal switch & I had taken the shutter shroud off to inspect the thermal switch, I elected to go ahead & replace the thermal sensor switch since I was already 90% there as far as installing a new one. But that was no help as I still had random engine shutdowns that eventually became more frequent...like as soon as I let go of the Start Switch. I then replaced the oil pressure switch and bingo, no more shutdowns!

Both the thermal switch and oil pressure switch are fairly common parts. I found the thermal switch at an online lawn mower shop & it was ~ $15. The oil pressure sender is even more common & can be found locally or online. I don't have the civilian part #'s now but if I can find them, I will post them.

You can find the part #'s in the TM (-24P) and can cross reference to various mfg's part #'s when searching online.

 

[Guyfang]

On the whole, such shutdowns are about 97% oil pressure switch. The thermal switch has a lower failure rate.

 

[Light in the Dark]

I've had in maybe a dozen air cooled sets over the years, and the only shutdown failures were due to LOPS. Never once the shutter switch.

 

[rickf]

My LOPS went bad, still have it bypassed and just watch the oil pressure gauge but I really need to get that fixed. But on mine I did notice that the shutters were not opening very far at all. I took it all apart and cleaned everything up and I did find a lot of dirt in there but at least no nests. Once all the rusty linkages were freed up the shutters work just fine now. They don't even think about opening in cold weather. So basically even though I was not getting overheat shutdowns I am sure it was getting pretty hot when running in hot weather. It is always a good idea to check all these things no matter what.

 

[Ray70]

My LOPS went bad, still have it bypassed and just watch the oil pressure gauge but I really need to get that fixed. But on mine I did notice that the shutters were not opening very far at all. I took it all apart and cleaned everything up and I did find a lot of dirt in there but at least no nests. Once all the rusty linkages were freed up the shutters work just fine now. They don't even think about opening in cold weather. So basically even though I was not getting overheat shutdowns I am sure it was getting pretty hot when running in hot weather. It is always a good idea to check all these things no matter what.

Let's go Rick... get on it! Don't risk a spun bearing over such a simple fix. You can't watch the gage 24/7 during an outage... and I think we all know, nothing ever breaks when it's most convenient for US!

 

[Guyfang]

I've had in maybe a dozen air cooled sets over the years, and the only shutdown failures were due to LOPS. Never once the shutter switch.

After posting, I sat here and thought long and hard about the Thermo switch. I can remember 2 times I had to change one, and that was because the switch and housing was damaged. But never changed one because it was bad.

 

[rickf]

Yea, I am going to rob the LOPS out of my other 002 that I keep telling Ray I am going to get working on and then weather of life keeps getting in the way. I will swap the bad on in my good set for that one and put a note on the control panel to that effect.

 

[Guyfang]

Soak the LOP, and use light air pressure to move the piston and spring in the LOP. Cant hurt. By in the 80, I did that twice on other sets, and it worked. The worst that can happen is nothing. Or better said, if its broke, you cant make it broker.