MEP 831 FAQ for owners or potential buyers

[paraclete comes]

Just wanted to post up a few facts that might help those out looking for an MEP 831a 3kw diesel generator or already own one. This will get updated as I find more information so please be patient with me.


DRS Fermont's 3kW Tactical Quiet Generator Set is the first Generator Set produced for the US Military with a Permanent Magnet Generator (PMG) and variable speed technologies to pass rigorous Government qualification testing.

Power output	3kW @ .8 power factor
Voltage	120, two wire; 120/240, three wire
Engine	Yanmar Diesel, L70, Air cooled, manual & electric start MORE SPECIFIC the Yanmar L70AE-DE-
Generator	DRS PMG
Sound level	69 db at full load
Fuel tank capacity	8 hour tank
Tests	MIL-STD-705 and MIL-STD-810
Fuel	JP-8, DF-2, DL-2

Mechanical
Dimensions
(LxWxH inches)	34.5 x 27.9 x 26.5
Weight
(Dry without battery)	270 lbs

This generator runs the following consumables:

Factory Battery- concorde RG-24-15A1 (please note however this battery is only sold to the government and although you can obtain this on the surplus market the civilian equivalent is readily available)

Commercially available Battery- concorde RG-24-15 (note this battery is identical in size and performance to the A1 battery specified by the military. The only difference is it is certified for aircraft and has #8 metric terminals instead of standard auto clamp on type terminals. You can easily convert your mep831a terminals to fit this battery. You will need two 5/16" ring terminals to convert this. Once you have those simply remove the automotive clamps and install these ring terminals and your in business.

Air filter- yanmar 114250-12580

Oil filter- yanmar 114250-35110

In line fuel filter- hastings gf-27

Main fuel filter w/water separator- wix 33583

Glow plug-

Oil- 10w30 ( Oil should be changed every 100 hours and it takes a little over 1 gallon)

Fuel- jp8 or diesel (*note* if you run diesel occasionally add a lubricant such as opti-lube or Lucas or any other commercially available diesel lube. The epa has mandated removal of lubricants and it's hard on your injection pump. Also if you live in northern climates like me remember to use #1 diesel or at least a 50/50 blend in winter. That will lower the pour temp on your fuel and help prevent clogs in lines or filters.

As I get more information on this stuff I will update it. Also a big thanks to the guys that helped contribute the info to this.

Here's the TM for the MEP 831

http://greenmountaingenerators.com/w...15-639-13P.pdf

[Cord]

The engine is specifically a Yanmar L70AE-DE. It'll take 10w30 oil. Personally, I've been particular to the Shell Rotella product. Per Yanmar, oil change interval is every 100 hours and it'll take just a little over 1 quart. Checking the oil level is a bit different from what we might be used to; with the unit level, fill the oil until it's level with the mouth of the filler port (per the TM 2 threads below, but that's really splitting hairs). The dipstick only reads amounts that are less than full. To read the dipstick don't thread it in, just rest it in the opening. The filter really isn't changed all that often. It's more of a screen that's screwed into the engine than a filter.

If you are starting in cold weather (or are lazy and just want the engine to start on the first pull) remove the rubber plug on top of the engine and put several drops of engine oil in the hole. It's some sort of starting aid it works freekin' awesome!

[R Racing]

Is that the square hole to the right and below the valve cover?

[Cord]

That sounds about right. It has a square black rubber plug. Remove the plug and you'll have a round hole with a small black hole in the bottom. I've tried tipping a little oil in from a quart bottle and usually make a mess of it so I've switched to using an oil can. The amount of oil doesn't appear to be critical. With the oil can I give it one shot, with the bottle I'll over fill it. Starts just as well either way. Oil viscosity doesn't seem to be critical either. I've been using cheap farm grade 30w.

[Cord]

Here's a question for others: reading through the TM, I'm wondering if a battery is required for operation when the set is manually started?

1. The manual references the direct current system "provides generator control circuitry, relay logic, and engine cranking".
2. Under "battery" section it says "If battery is not installed, battery cable ends must be isolated from each other, and positive end must be isolated from ground. Failure to isolate battery cable ends could result in severe electrical discharge. When not connected to battery, connect battery cable ends to plastic storage stud."
3. Under manual starting it says "Note: If generator has an operational battery installed, it will be necessary to reset the LOW OIL PRESSURE (10) fault on the malfunction indicator module..."

I haven't seen anything in the manual disallowing usage without a battery.

[R Racing]

I would say yes you could run it without a battery and insulate the + lead. On a second note whats the thin red wire laying on the battery ? I have seen them on several units laying loose in the cabinet ?

[Cord]

Connection for the solar battery maintainer. The chargers appear to be field installed, hence the sloppy wiring and crimp connectors.

[paraclete comes]

thanks for the great info guys

[Cord]

Well, this is what I get for being an internet expert when I haven't touched the gen set. I know the Yanmar engines as I currently own two of the air cooled ones. Both of these have the oil starting assist. I see that for what ever reason, the hole is plugged on the generator. Oh, it's still there, but it's plugged from the factory. Living in Wisconsin, I know that I'll want this feature so I'll try to add it. If successful, I'll post some pics of the process. There are pics in the attachment below.

[Cord]

It's nearly impossible to get a picture of the engine serial number because it's under the muffler. Because I have my engine torn apart, I was barely able to get a pic of the plate. To order any parts from a Yanmar dealer, you'll need the model and serial number.