MEP-802A Coolant Bottle and Intermittent Surging Issues

[Mainsail]

I was getting the genset ready for the big storm tonight....

Started the 802 and the radiator cap was leaking a pretty steady drip. Took it off and cleaned the surfaces and it appears to have stopped the leak. The crap part is now there's coolant and I can't tell what's residual (because it's slimey coolant) and whether there's another leak somewhere. Blew it off with air, wiped it all down, but still can't tell.

Decide to pull the coolant recovery bottle bracket off so I can clean up behind it and check for leaks, and the nipple on the bottom of the bottle broke.

What's available for a replacement? In the process of trying to do a field repair of this one I completely ruined it, so it isn't usable at all now.

 

[Jeepadict]

In the interim I would put the overflow tube in a Mason jar with a hole drilled in the lid. Use something to wrap the glass to isolate it from the vibration and zip tie it in the same place. Not perfect, but will get you by.

As I understand, the original bottle is discontinued and unavailable. There is a suitable substitute I've read about, but the specifics escape me at the moment. I'm sure one of the experts will chime in with better details. There's several fellas on here with parts machines, you may be able to source one that way.

I reccomend you make a post in the "parts wanted" section letting folks know you're looking.

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[Ray70]

Poke around a little, you'll find several threads about using the bottle from a Suzuki Samurai ( 1987 vintage )
Available on the internet for like $15'
You need to alter the hoses slightly, but it fits right into the bracket with 2 big zip ties.

 

[Mainsail]

Well, attempt to salvage #1 was to heat the remainder of the nipple with the heat gun and jam a 1/4x3/8ths adapter in the hole. That didn't work, just melted the nipple and the adapter.

Attempt #2 I attempted to grind off the melted nipple but the motorcycle is in the way, and because I couldn't see it well I ended up grinding a hole in the bottle.

JB Weld is attempt #3 - it isn't a pressurized bottle anyway. While I was waiting for that to harden the power went out...

The epoxy fix seems to be working for now, but the original problem of the radiator cap has returned. It isn't even up to pressure and the cap is dripping pretty steady. I swapped in the cap from the CUCV M1009 and it stopped the leak, however I'm sure it isn't rated at only 7psi like the MEP cap is.

I'm watching it all closely but were on gen power for now.

 

[Mainsail]

Bottle holding great so far but...

Having weird random surging at 50% load. Having it at 60 or 100% load. Runs fine for an hour or so, suddenly starts surging. Swapped back to the internal tank helped a couple times, but not every time. Some of them are bad enough that I have to open the contactor and let it recover.

It just turned 28 hours. I like that it's powering the house great, don't like that I have to babysit it.

Possible causes?

 

[Jeepadict]

Good practice is, new problem starts a new thread.

It seems problems like this is common in low hour units, from sitting all those years. The boys will give you things like checking pumps and filters...injection pump timing...cleaning the injectors & IPs sometimes help...some end up removing the front radiator stack to get behind the front engine cover to mess with the governor mechanism.

You can also dig in to the TM and go thru the troubleshooting steps in there.

Fyi, you weren't switching back to the internal tank, you were disabling the aux pump from cycling to maintain the level in the day tank. (This assumes your machine isn't modified) Most likely just coincidence, I'm reading you have some gunk in a mechanical component in the fuel system.

These machines have a reputation for being tough when up against hard use, and they are in their simplest form. At the end of the day it's an imperfect machine built by an imperfect human. It's not "if" it's going to break, it's "when" and "how bad". Babysitting comes with the territory.

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[Light in the Dark]

Are you certain some high draw item isn't cycling on and off causing the governor to chase the load?

 

[FarmingSmallKubota]

Pretty easy for the water heater or well pump or something to kick on and draw a larger load than you thought.

 

[Mainsail]

The only uncontrolled loads are the fridge in the kitchen, a mini fridge in the garage, and a freezer in the garage. Those all cycled on this morning when I fired up the generator without drama.

Everything else is controlled things like lights and fans. All the lights are on, the furnace circulation fan is on, and a space heater is drying out the inside of the HMMWV. The HMMWV block heater is plugged in. It's currently at 50% load.

The gas gauge quit this morning
and is sitting off-scale high.

 

[Jeepadict]

The gauges are an easy troubleshoot. Follow the fault resolution in the TM.

Most likely the sending unit (float) crapped out (those suck to get out)...others could be gauge failure, chafed wire, or bad ground. Just follow the TM for the fuel gauge.

 

[Mainsail]

It's going between 40 mins to an hour of running/powering perfectly then some surging. The last surge it recovered by itself before I could get outside. As I was typing that it sugeged again and again recovered by itself.

So it seems to bog down, the freq needle swings back and forth, and some black smoke comes out the exhaust. Oil pressure is solid at 45psi and the temp steady at about 165.

 

[Jeepadict]

Since nobody has said it, I'll do the honors.

You should prepare yourself for that machine to be a Gremlin-filled PITA in the first hundred-ish hours or so. Most of the MEP generation are in the 30 +/- year old category...and old stuff sitting for years usually doesn't like to behave when you kick it back into immediate full duty use after an extended slumber.

 

[Ray70]

Ah, it won't be that bad... ( hopefully ) just need to exorcize the demons that moved in over time.
Fuel gage issue is 99% likely to be a bad sending unit. Search this site for info on replacing it with a 5.5" WEMA marine sender.
It's very easy, about $55 ( cheaper if you go with a no name China knock-off ) and way more reliable than the old float arm and rheostat junk.
On the surging, you can try ( if you haven't already ) using seafoam or ATF in the fuel to clean things out. Give it a good workout to clean any carbon out of the exhaust. If the problem persists, try reading the TM section about the governor droop setting.
Perhaps you are just on the fringe of the set point where governor "over sensitivity" causes it to hunt around, particularly when the load changes.
You may need to back off on the sensitivity just a little.

 

[Guyfang]

Take the fuel tank cap off. Remove the screen. Look in the tank with a good flashlight. The diesel should be clear. Is there a lot of trash in there? Several times I have had problems like this, and it was because something was floating around in the tank. Every now and then, it would come by the fuel pick up, and be sucked up ON TO IT. Not in it, on to it. The electric fuel pump continues to pump, causing a vacuum at some point. Engine starts to stumble, the engine starts to spool down, and the trash floats away. This was one of the, "tear your hair out" problems, that can drive you mad.

It would be also good, maybe for you to set out in front of the control panel, after it has been running good for a while. Keep your eye on the percent of load meter. If it go's up and the engine starts to stumble, then you know SOMETHING is overloading it. And if not, than this is one more thing you can exclude from the possible failure causes.

 

[Mainsail]

It seems to misbehave with either the external or internal tank. That said, my last post was two hours ago and it hasn't stumbled at all since then.

Fingers crossed...

 

[FarmingSmallKubota]

So it sounds like it could be a stuck float reading empty because if you are on aux then that means the aux float is not kicking on and filling the day tank therefore running out of fuel, and since your fuel gauge is NLA then you have no idea if its working

 

[Jeepadict]

It seems to misbehave with either the external or internal tank. That said, my last post was two hours ago and it hasn't stumbled at all since then.

Fingers crossed...

Is your set factory configured or has the fuel tank system been modified? If it's factory, you are NOT switching between tanks.

In a factory configuration: When you rotate the start switch to Prime & Run, only the Main pump operates. When set to Prime & Run Aux fuel, the Main pump runs AND you are enabling the Aux pump to cycle draw from an outside auxiliary source to maintain the on-board (day tank) between approx 1/4 and 3/4 fuel level without user input. The Main pump never shuts off, and the engine is always being fueled from the internal day tank...if everything is operating correctly.

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[Mainsail]

Is your set factory configured or has the fuel tank system been modified? If it's factory, you are NOT switching between tanks.

In a factory configuration: When you rotate the start switch to Prime & Run, only the Main pump operates. When set to Prime & Run Aux fuel, the Main pump runs AND you are enabling the Aux pump to cycle draw from an outside auxiliary source to maintain the on-board (day tank) between approx 1/4 and 3/4 fuel level without user input. The Main pump never shuts off, and the engine is always being fueled from the internal day tank...if everything is operating correctly.

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Interesting. So I wonder if with all the rain and high humidity it could be a water issue. The tank output has a filter with a water separator and when I drain some I'm not seeing any water.

 

[Guyfang]

Exactly!! Thats why, on main or AUX, its all the same. The fuel for the engine comes from the tank. ALL military gen sets work this way.

 

[Jeepadict]

Interesting. So I wonder if with all the rain and high humidity it could be a water issue. The tank output has a filter with a water separator and when I drain some I'm not seeing any water.

In your earlier posts it sounds like things are improving as those internals are starting to get moving again. Fresh fuel and SeaFoam in the tank, and some ATF in the oil a few minutes before your next oil change may prove to work wonders.

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