New to me PU798A (Mep-803a on a LTT-TQG high mobility)

[Daybreak]

Howdy,
PU-798A High Mobility Power Unit, Silver Eagle LTT-TQG, with MEP-803A 10kw TQG

 

[Daybreak]

Howdy,
I did some touch-up painting on the engine. It's surprising how much condensation drips off the engine with the temperature changes. Anyway, I have come across a matching color engine paint.
Thread covering DN2M and DN4M engine paint here
Here are some before pictures.



Here are some after pictures.

 

[Guyfang]

Clean looking machine Mike!

 

[Daybreak]

Clean looking machine Mike!

Howdy,
Thanks.
After going to town on it with a pressure washer. The stickers really were on there. All over the place. Then after all the wet stack goo which drizzled all over, the inside looks much better too with paint touch-up.

 

[JRM]

That is a amazing engine paint job, wish I had that attention to detail. The paint on mine has been fried in the Barstow sun and is very chalk like- Couple of questions. 1. How much are the LTT-TQG trailers worth? Im half tempted to sell mine, or put a wooden deck on it and keep it. 2. Wet stacking is pretty rare on 4 cycle diesels as diesels run the "leanest" during min throttle- Do these units consume oil? I do know the old 2 stroke Detroit 2/71 gensets had issues but mine seems to blow really clean exhaust.
I pulled mine off the trailer and threw it in the back of my dodge for now- just to keep it out of the rain as I don't have room inside my 28x50 shop for the trailer

 

[Daybreak]

That is a amazing engine paint job, wish I had that attention to detail. The paint on mine has been fried in the Barstow sun and is very chalk like- Couple of questions. 1. How much are the LTT-TQG trailers worth? Im half tempted to sell mine, or put a wooden deck on it and keep it. 2. Wet stacking is pretty rare on 4 cycle diesels as diesels run the "leanest" during min throttle- Do these units consume oil? I do know the old 2 stroke Detroit 2/71 gensets had issues but mine seems to blow really clean exhaust.
I pulled mine off the trailer and threw it in the back of my dodge for now- just to keep it out of the rain as I don't have room inside my 28x50 shop for the trailer

View attachment 615723View attachment 615722

Howdy,
A lot comes from where the unit sits outside. Obviously sitting outside in Barstow will cook it, compared to where ever mine was on the east coast. My engine was getting the rust location from condensation. With the temperature swings and humidity, the cast iron block would be dripping with water.
The only time I know of these consuming oil is (bad rings, engine break in, low power generation) The wet stack issue is a thing with the MEP-8xx generators. Any time you have a lot of hours with a low power demand, you should put a good hard load on your unit to clean up the exhaust.

The LTT-TQG trailers recently sold in CA for a pretty price $$$. If anything, folks have taken the tires off and sold them, and mounted other tire+rims to lower the trailer too.

I like how you did the transfer from the trailer to your Dodge.

 

[Chrispyny]

Daybreak, i'm very curious where you purchased it. If you don't want to share, i understand.

 

[Guyfang]

Wet stacking has been a power generation problem for ever. The MEP-002 to MEP-006 sets had the same problem, if not worse. The military always allotted a generator much bigger then the job required. With good reason. Most units did not, could not and will never master, fingering loads. Most people have no idea how, and even when done right, it only takes one or two fools with a coffee pot and a microwave to spoil the figures. I once went to a communications site that had problems with the gen sets maintaining loads in the winter. After I took a pair of side cutters and clipped off the plug ends of four heaters, the problem went away.

 

[Daybreak]

Daybreak, i'm very curious where you purchased it. If you don't want to share, i understand.

Howdy,
I do not mind.
I purchased the PU-798A (MEP-803A) from GovPlanet at Chambersburg, Pennsylvania. So it was here on the east coast somewhere. I do not see the need for a woodland camo unit to be in southern California. I understand up in Washington and Oregon.

 

[Daybreak]

Wet stacking has been a power generation problem for ever. The MEP-002 to MEP-006 sets had the same problem, if not worse. The military always allotted a generator much bigger then the job required. With good reason. Most units did not, could not and will never master, fingering loads. Most people have no idea how, and even when done right, it only takes one or two fools with a coffee pot and a microwave to spoil the figures. I once went to a communications site that had problems with the gen sets maintaining loads in the winter. After I took a pair of side cutters and clipped off the plug ends of four heaters, the problem went away.

Howdy Guy,
I might as well share your PS Magazine article here

MEP 800 wet stacking information
View attachment PS MAG. Wet Stacking.pdf

 

[Guyfang]

Thats what its for, sharing.

 

[Guyfang]

I purchased the PU-798A (MEP-803A) from GovPlanet at Chambersburg, Pennsylvania. So it was here on the east coast somewhere. I do not see the need for a woodland camo unit to be in southern California. I understand up in Washington and Oregon.[/QUOTE]

Dont forget that these sets are being sent from all over the world, back to the USA. Saw some ready for shipment in Graf Germany yesterday. A buddy of mine there who is the "Expediter" for equipment transportation said they are going to Andover. From there its anyone guess.

 

[Chrispyny]

I purchased the PU-798A (MEP-803A) from GovPlanet at Chambersburg, Pennsylvania. So it was here on the east coast somewhere. I do not see the need for a woodland camo unit to be in southern California. I understand up in Washington and Oregon.

Dont forget that these sets are being sent from all over the world, back to the USA. Saw some ready for shipment in Graf Germany yesterday. A buddy of mine there who is the "Expediter" for equipment transportation said they are going to Andover. From there its anyone guess.[/QUOTE]

Andover, MA?

Goodness, my mouth is already watering!

 

[JRM]

probably swapping them out for the new AMMPS Cummins units. Wonder when they started shipping old stuff back? when my father was in the service they left everything- heck they pushed willies jeeps overboard back in the day.

 

[Guyfang]

I would take a picture for you guys, but now a days that is risky. The MP's and the security wiesel's like to find people who use a camera on post! Oh yeah, that got real interesting for me once in Bamberg.

Yeah, Andover, Ma. About 45-50 sets along with lots of trucks and trailers.

 

[AOR]

Does anyone know if wet stacking can cause power output issues?

I purchased some more of these in unknown condition. I have 2 machines with power output issues that are both wet stacked



1 of them is registering a 75% load with only shop fluorescent lights on that registered 25% on others
when I turned on an AC unit the surge tripped the overload breaker where others were able to run all the lights plus 2 AC units and 5 fans at 75% load




a second machine only makes the lights flicker

The machine that makes power does not push the exhaust flapper open all the way and it sounds different
I am sure the exhaust is clogged up

 

[Daybreak]

Howdy,
I found that a wet stacked unit does have problems keeping a load. I started loading, and letting it run, and loading more. Yes, the sound is different. It is congested. Wet staked can also damage the rings and piston walls beyond being able to bring it back. As I and others have said. A severely wet stacked unit needs to run with a good load for a long time. I can now run my MEP-803A without issue at any load up to 133% At first I could not.

I have seen statements saying a good 100% load for 8 hours would help.

Good luck.

Maybe Guy will have some insight to other items to look into

 

[kloppk]

... 1 of them is registering a 75% load with only shop fluorescent lights on that registered 25% on others
when I turned on an AC unit the surge tripped the overload breaker...

I suspect the problem here is dirty contacts in the AM-VM switch. Part of it's function is to connect the "burden" resistors to the output current transformer. If the contacts are dirty they will cause added resistance in the burden resistor circuit. The short story is that the dirty contacts will make the genset "think" it has a higher load on it than the actual load causing the %Load meter and the overload relay to think there is a much greater load on the generator than what's actually on the generator.

I found that by "exercising" the AM-VM switch that it will clean the switch contacts and eliminate the problem.
My 802 experience the same problem until I exercise my AM-VM switch. After that it correctly sensed the %Load.

...a second machine only makes the lights flicker...

Do the generator Voltage & Frequency gauges read OK before and after applying the load?
Might want to put a handheld Voltmeter on the output to verify it's OK.

 

[Guyfang]

We sprayed contact cleaner on and into the S-6, and sometimes that clears up the problem. But sometimes not. A new S-6 then is needed. PITA to change. Also check that EVERYTHING is tight. Loose connections will also give the same faults.

Yes, a load test is always good. Start with maybe 3 KW, run it for several hours. Step it up to 5-6 KW, and run it some more. Continue till you can run it 130 % load. The S-6 proved to be such a PITA, that it became a part automatically changed during reset. No test, simply toss it. So yes, you need to test it. Pull the top skin, and rotate the switch. Feel smooth? Feel hard to turn? Mybe only in certain positions? It IS possible to take an S-6 apart, and inspect it. Putting it back together is the problem. No one can ever entice me to try it again. I am ashamed to admit, I failed 4 times. Tossed them all away. So if you feel like you have nothing to do for 5-6 weeks, go ahead.

When you say the exhaust flap doesn't open fully. Try placing your hand LIGHTLY, MOMENTARILY on the exhaust manifold just after starting the set. Both outputs the same temperature? Are both cylinders firing?

You can also remove the muffler, heat it up and clean out the crap in it. Can't hurt. When an engine has restricted exhaust output, its not good.

 

[Daybreak]

Howdy,
The unit started and ran. The sound was slightly muffled. I also had wet stack black goo around the exhaust manifold and muffler. That is just one of many reasons why I took it apart and physically cleaned the muffler, exhaust manifold and what I could reach on the head. I replaced all the gaskets. Exhaust manifold gaskets, and the muffler gasket. I got it all back together, and ran it loaded for a while. You can see the video earlier in this thread. Yes, it still smoked some, probably because of the wet stacking on the walls, pistons and rings. That is why I did not put all the panels back in yet. At this time I also replaced all the fuel return lines, since they were weeping fuel.

The MEP-803A runs great. Starts instantly, and runs smoke free. I have not had any issues after cleaning up the wet stack goo.