MEP-002A Exhaust Question plus Machine Resurrection

[Tinstar]

Picked up a 1990 MEP-002A this past week from GSA.
It’s mounted on a M116A2 trailer.
No clue yet if it runs or makes power but should know by next week.
Fuel system is a disaster but fixable.
Still have to check the IP.

Generator will stay mounted on trailer

Plan is to fabricate a solid exhaust extension or use the flexible Stainless exhaust pipe and come off the factory exhaust 90 degrees and exit the bottom of trailer.
A second muffler will not be used.
Pipe will be wrapped with Header Exhaust Wrap and the extra weight supported.
This should, I’m hoping, to quiet the noise a bit.

My question (finally) is this…….
With the extra length of pipe, will this create too much back pressure and cause the unit to run hotter than normal?
Should be no longer 4’ max.

My NF-2D generator route’s its exhaust this way and it’s really quiet.
I know Kubota liquid cooled and Onan Air cooled engines are two completely different animals.

Thanks

 

[Light in the Dark]

Most of the running noise on those machines is created by the genhead, not the engine. Good luck getting it operational.

 

[rickf]

If you walk in front of the exhaust of a running 002 or an 003 you will notice that the exhaust itself is not very loud. The engine itself is very loud since it is a diesel and it has no water jacket to muffle the compression ignition. Blowing the exhaust out the bottom will make it very uncomfortable to be anywhere near that machine!!!! If you want to use that theory then direct it straight up with a rain flapper on it.

 

[DieselAddict]

+1 on not worrying too much about exhaust noise.

You will get far better results from building some sound isolating walls to put up around the engine itself. I have a MEP003 with the ASK and it made a very noticeable difference to reduce the clacky higher frequency sounds that can be harsh.

Putting a vehicle between the generator and where you sleep also does wonders.

 

[Tinstar]

Ok
Great advice guys!!
It makes sense.
I have not heard one run since my early army days.
Sure I can listen to YouTube videos of them running all day long but it’s impossible to get the full depth of the noise.

I will not modify the exhaust.

GSA had another trailer with the same generator but with the ASK kit installed.
I really didn’t know any better about the ASK kit and the trailer was set up for something else and had a ton of racks and such that I did not want.
Didn’t have the Bows either.

Oh well

GSA basically gave this one away so I’ll make it work.

 

[Guyfang]

There are some who like the ASK, and some who don't. Users love it because of its sound reducing effects. Mechanics hate it, because if you got to do something other then an oil change, its a huge PITA. Yes you can take the panels off. But what a PITA. So its all what you value most. When the ASK's came out, what a rush! Everyone and his dog wanted one. We installed them like giving away free beer. There where huge piles of doors and things we removed in the DRMO's. Huge piles. I kept mine, and made a long list of people hate me for "Keeping junk!". 5-8 years later, people would give you their first born for a pile of "Junk" doors and tops. And, if you had to wash out a gen set, mostly the one you got in return, was without ASK. If you had to turn in your dog gen set with ASK before you got a replacement, you had no ASK when the replacement came. If you were foolish, and let someone hornswaggel you out of your doors and tops for some ASK junk, well, it was a PITA. They were never compleat. Buying a used one is to be taken with a grain of salt.

 

[Tinstar]

I really don’t care that it doesn’t have the kit.
I just hope it runs and produces power.

 

[Tinstar]

Just cleaned up the fuel system canisters.
One was rough and the other two not bad.

Filters were far worse than the canisters.


Bases are more stained than anything.
Strainer canister rod was already busted but rest of it is intact and in good shape.

Fuel tank was 3/4 full of liquid.
1/4 diesel 1/2 water.
(Tested the diesel using a soaked paper towel and it burned just as good as the fresh stuff)
Smelled horrible.
Drained tank and it had about 1” of crud on bottom.
Cleaned tank and the bottom is like brand new. Couldn’t believe it.
There is some slight rust above the liquid line but light surface only. It’s cleaning up nice.
Fuel level float guides had surface rust also.
It cleaned up great and float rides smooth

Good news is that when I pulled the lines to the pump, pure diesel came out. No water.
Still need to check the IP out.

Engine oil looks good and I removed the valve cover to see if water/moisture got inside engine.
Looked new inside.



Ordering filters tomorrow.
I want to see if this thing works before buying the filter adapters.

Pump screens cleaned up great also.

 

[Chainbreaker]

When you do get to the point where you think you're ready for a start-up I would fill the last cannister before the IJ Pump with straight Seafoam. Prime & let sit overnight and then attempt a startup.

However, if you think any of that contaminated fuel with water might have entered the IJ Pump you would be better off making sure the IJ Pump plunger guide is not stuck (search this forum on how, lots already written). If it were stuck and you attempt a start-up you could break the plunger guide inside the IJ Pump. As long as it's an Ambac model pump & NOT a PSU model pump (PSU has screw out bottom facing downward) you can buy new plunger guide, not so with a PSU Pump. Though being a "1990 vintage" MEP-002a it "should" have the AMBAC IJ Pump.

 

[Ray70]

Luckily he does have an Ambac pump, but needs to be sure its free none the less! Lots of posts on here as to how to do it, but filling with acetone or seafoam, lacquer thinner, carb clean... anything like that then let sit a few days.
I like to pull the delivery valve and holder out so you can see if the plunger is turning and moving in and out.
If not moving in and out, tap it in with brass punch and hand crank it some more.... repeat until plunger if moving in and out 1/4" as motor is turned by hand.

 

[Tinstar]

Will do the SeaFoam for sure. I use it in everything I own. Love the stuff.
It is a AMBAC pump.
I did turn engine over by hand 1/2 revolution to make sure engine wasn't seized.
Have read in old threads that doing even that probably did damage if pump was gunked up with sticky old fuel.
Power hasn't been applied to unit yet.
No critter damage is visible. Lots of Mud Dauber nests.

I don't think water entered pump, but did find a can of starting fluid in the tool box mounted on trailer. Could be a very bad sign. Will find out soon enough.
Unit has 2064.9 hrs, so lots of life left in it hopefully.
Fuel tank had so much water in it, I think, because all the fittings and gauge on top of tank didn't have one ounce of thread sealer. Just bare metal to metal contact.
I did lose about 1-3/4" of the fuel pickup tube due to rust. Rest looked fine. Will be using AUX fuel anyway.

All Filters should be here by the end of the week.
Bought all filters from Oshkosh Equipment. GMG was more expensive and insanely expensive on shipping.
Canisters cleaned up great.
Fuel tank is soaking with diluted acid to finish cleanout
Fuel Fill strainer and cap are soaking in Evapo-Rust.
Hoses all cleaned out, but will do it again once everything is back together.

NOS fuel hose from check valve to IP inbound. Unit had rubber hose and hose clamps on it when I picked it up. Just that one hose.
Stainless 5/16-18 threaded rod for busted strainer canister rod inbound
Aux Fuel hose kit inbound, still needing the bung.

Misc air cleaner parts from SS member Ray70 located.
AMBAC M50 rebuild kit from factory inbound.

The injection pump is the most intimidating.
Really don't want to remove it but betting I will have to .
Yes I have of course all the TM's downloaded. Will be loading them on a memory stick and heading to Staples for printing and binding.
Prefer to look at paper instead of a screen.

Found lots of info on the pump but still searching for How to tell if Plunger guide is busted without tearing it apart. If that's even possible.
Lots of threads still to read through.

This is my first "true" Military generator.
It might turn out to be junk, but I will give it every chance to live again.

 

[Ray70]

Unfortunately there's no fool-proof way to tell if the plunger guide is broken with 100% accuracy.
You can pull the center cap, delivery valve and holder off the pump and look in the center of the pump while turning the engine by hand.
The plunger should be rotating at 1/2 the speed you're turning the engine and it should be plunging in and out about 3/16 - 1/4"
However, the plunger guide can still be broken and the sticky fuel gum can be what is turning the plunger, not the plunger guide.
Also, some times the plunger guide doesn't completely snap, it just skips 90 or 180* and then grabs again. If so, the plunger will be turning but way out of time causing the motor to run poorly and not build RPM correctly as well as overheat quickly.

You can try testing the pump timing using the pump flow method described in the manual, but that can't be done until the IP is assumed to be free.
It the machine fails the timing check miserably, the plunger guide has either skipped or broken.

My suggestion is to take the fuel pump fitting you have, screw it into the IP with 2' of 3/8" hose running up vertically.
fill the IP with seafoam by pouring it down the hose.
use some air pressure to force the seafoam into the pump, then repeat.
keep it full and let it sit a couple days.
remove the delivery valve and holder after a few days and rock the motor back and forth a little bit.
See if the plunger appears to be spinning. If it is not spinning take the pump off and rebuild.
If it is spinning but not plunging, tap it in slightly with a brass punch or a wooden dowel until it moves in and out when rotating the engine.
If you can not get it to rotate and move in and out, remove and rebuild.
If its free, attempt to start it. If it cranks a lot but no smoke at all out the exhaust, the plunger is probably either sticking or not spinning under pressure and will need to be rebuilt.
If it starts hard and runs but won't take a full load or if the valve cover gets hot and air shutters open within a few minutes the plunger guide has probably skipped and needs to be checked.
Lastly: The TM shows how to rebuild the PSU pump, the pictures etc. in the TM are incorrect for the Ambac pump.
If you don't have the Ambac M-50 rebuild instructions, send me a PM with your email address and I can forward them.
Don't be afraid of removing the IP. it's not that bad and I have learned a few tricks over the years to make it easier to get it right the first time.
Worst case scenario if you can't get it going, take the pump off and send it to me along with the kit and I can rebuild it. I've done dozens of them over the years.
Once the pump is done, the next weak link in the engine is the injectors, IF any water got in them from the fuel, but we can cross that bridge if necessary!

 

[Tinstar]

That’s exactly what I was looking for.
Will do just that.

Thank you

 

[Chainbreaker]

...I don't think water entered pump, but did find a can of starting fluid in the tool box mounted on trailer. Could be a very bad sign.
I did lose about 1-3/4" of the fuel pickup tube due to rust. Rest looked fine. Will be using AUX fuel anyway.

Even if water didn't infiltrate the IJ Pump old fuel that turned into gummy varnish & sat within IJ pump over time can wreak havoc. Ray70's advice on the IJ Pump is right on the money!

The prior use of starting fluid may be a symptom of problems with glow plugs and/or the intake manifold heater elements and circuitry. As long as whomever used the starting fluid didn't use much you should be OK without any damage to engine internals.

You might be OK with the shortened fuel pickup tube if your AUX fuel keeps the fuel level above the now shortened main fuel pickup. Though I don't think it would be that hard to replace or extend the tube itself (possibly sleeve it with extension tube) to get pickup length to spec. But first things first, making sure it's a good engine & produces proper AC output.

The MEP-002a/-003a are robust units & fairly simple units to own & maintain unless you end up with one that was previously abused or otherwise damaged beyond economical repair.

 

[Tinstar]

The IP throttle linkage moves fully and freely up and down without hesitation or sticky spots.
Feels smooth

Will check for plunger movement tomorrow if it’s not raining.
I have the set covered with a canvas tarp.
The original covers for these trailers just don’t exist anymore.
Will see if Ray70 has a spare pickup tube. If not I’ll post in classifieds.

The fuel in tank was old and smelly and lots of crud, but not really sticky or gummy anywhere that I could find.
I’m sure it’s there somewhere where I don’t want it.
I’ve seen that before on old tractors.

 

[Tinstar]

Fuel tank looks surprisingly good after draining and washing the crud out.
No pitting and looks like surface rust only.

She’s soaking now with a diluted acid mix.

 

[Guyfang]

This is my first "true" Military generator.
It might turn out to be junk, but I will give it every chance to live again.


Oh ye of little faith! You got to believe Brother!

 

[Guyfang]

As long as you time the engine before taking out the IP, 90% of your worry's are cured.

 

[Tinstar]

This is my first "true" Military generator.
It might turn out to be junk, but I will give it every chance to live again.


Oh ye of little faith! You got to believe Brother!

I flew helicopters for 33 years.
Multiple Combat Deployments.

I lived by “Hope for the best, EXPECT the worst”

 

[Tinstar]

As long as you time the engine before taking out the IP, 90% of your worry's are cured.

I did this just fine on an old 67 John Deere 2020 Diesel Tractor I rescued out of a field where it sat for 15-20 years.
Timed engine, removed pump, had pump rebuilt, reinstalled pump, bled it and she fired right up.

I think this has me a tad nervous since I’ve never owned one of these before and not familiar at all with them.
Good thing is the process has been well documented and lots of help from everyone here.

Having a pump with parts still available is huge.

The JD tractors Injection pump was a long discontinued model and parts were scarce and expensive. It was well over $1000 to have rebuilt.
Lots of IP rebuilds are this pricey but this tractors pump wasn’t supposed to be.

At least I know how to start it.
So many YouTube videos of improper starts on these machines.

I do love a challenge and enjoy working on this.