MEP-004 purchase = lots of learning ...

[tcruwithme]

So, I got an MEP-004 from Government Planet about a month ago. It was advertised as non-functional with the problem described as "unit runs only when start/stop switch held in the start position." To me, that sounded like a fixable problem. I won the auction and towed the MEP-004 on the M201 trailer 240 miles home to Minneapolis.

I charged up the batteries, and they held a charge overnight. It turned the starter over, so I thought batteries were good to go. The TM troubleshooting section had this exact problem described. It said to replace relays K1 (Relay, Start-Stop), then if still not working replace relay K2 (Relay, Over-voltage), and then if still not working replace relay K8 (Relay, Fuel Level). At about $50 each relay, I obviously needed all three. The K8 relay was the problem, so those other two were probably fine. Oh, and even though the K1 and K8 relays had different part numbers, they are the exact same thing. Nice.

After the K8 relay was replaced (pain in the ass), the starter would no longer turn over. The batteries were shot. Great.

I replaced the batteries, and now the unit starts and stays running. The convenience outlet is all messed up, but that's an easy and cheap fix. The fuel sending unit doesn't work, so that's another $60. At least I got to order that from Saturn - those cats are pretty cool.

Next weekend I'll replace the sending unit and convenience outlet. At that time, I'll put a load on it and see how it does. Fingers crossed ...

 

[Crawdaddy]

If the relays are anything like the MEP-002/003 ones, each relay is actually 2 sets of contacts with one set not used. Flip the relay upside-down and you have a fresh relay.

 

[tcruwithme]

Thanks for the tip. When I removed the K1 relay from the control cubicle assembly, I didn't pay attention to which way it was set in the board. The two sides of the relay looked exactly the same, and there was no indication on the generator or in the TM as to which way to put the relay in. So, I suspected it could be put in either way, as you stated below. The K1 and K8 relays are the same, but they do have a blue ring around one pin on one side of the relay. That's interesting ...

If the relays are anything like the MEP-002/003 ones, each relay is actually 2 sets of contacts with one set not used. Flip the relay upside-down and you have a fresh relay.

 

[Guyfang]

The blue ring is one side of the coil, X-1 and X-2, When you look at the side of the relay, you see a diagram of the relay. The coil is shown plainly on the relay. Next time, insted of getting parts, try jumping the relays instead. Cheaper that way. So what is wrong with this set. I know them very well.

 

[tcruwithme]

Thank you for the advice, Guyfang. When I bought it, the Government Planet auction page said that it would only stay running while the start/run/stop switch was held in the start position. The troubleshooting section of the TM had this exact problem listed, and it advised to replace relays K1, K2, and then K8 (in that order). I didn't know the batteries were shot at this point, because the genset was turning over while cranking. I also noticed that the fuel error indicator light was on, but I didn't know if that would clear correctly when the genset was not running normally. Now that I know a little more, the fuel error light would have pointed me to replace relay K8 first, and that would have solved the problem.

I have since replaced the batteries, and it now starts and runs. I need to replace the convenience outlet cover, as that is broken. While the fuel error light is now off, the fuel gauge is reading empty when there's a half a tank of fuel in it. I got a new fuel float switch from Ebay, and I need to put that in this weekend to see if it fixes my gauge problem. I had to replace the fuel float unit in my MEP-802A not long ago, so it would not surprise me if this is the problem with the fuel gauge.

After that, I want to get the rust spots treated and repainted.

The blue ring is one side of the coil, X-1 and X-2, When you look at the side of the relay, you see a diagram of the relay. The coil is shown plainly on the relay. Next time, instead of getting parts, try jumping the relays instead. Cheaper that way. So what is wrong with this set. I know them very well.

 

[Guyfang]

Before you bought the fuel level sending unit, you should have taken out the old one. Sometimes it was only the screw that holds the float arm to the wiper arm. Or sometimes the float bulb simply slipped out of the float arm. If the old float is full of fuel, then find the hole, heat up the hole with a SMALL torch or a bigger soldering iron. Use solder paste and then put a DAB of solder on it. Get a good solder point, not a cold solder. Keep it on hand as a reserve. Do not use Black RTV to put the sending unit back in, or at least use a RTV that is meant to be used with diesel. Hopefully the new sending unit comes with a new cork gasket. Then no RTV is needed.

When ever you have a fault that shuts the engine off when you let the S-1 start switch go to the run position, restart, hold up the S-1 and turn on the S-7 Battle Short Switch. Then let S-1 go. If the set continues to run, you have a safety problem. You can jump each relay and find the bad one faster then changing parts.

Also check the fuel tank gage. The procedure is in the book. Shout at me in a PM if you need the books.

Take a bunch of pictures of the inside and outside of the gen set and trailer. I might be able to see if anything is missing. I spent lots of time repairing these kinds of generators.

Last but not least. When sanding the rust and paint off, wear a mask, eye protection and a paint suit. A paper one. CARC paint is a carnagenyc. Breathing the dust is not good, or getting it into your eyes.

Have fun, this is a great generator!

 

[tcruwithme]

MEP-004A - what's this part on the fuel p

Well, I replaced the fuel float in the main tank, and I still have an issue with the gauge reading low. There is 10 gallons of fuel in it, and the gauge reads just over a quarter tank. I'll find a gauge to swap it out and see where I'm at.

My next question is about a part attached to the fuel pump. The part that looks like it should have something connected to it is called "Lever, Adjusting" in the TM (TM 9-6115-464-24P).



There's nothing attached to this part in my genset, but it looks like there should be something connected to it based on what's in the TM. The image below is Figure 67 in the 24P TM.



If anyone has advice as to what this could be and how it should look in my genset, please let me know. Thanks for your help!

~ Thad Carlson, Eagan, MN

 

[Guyfang]

OK, there is several applications for this gen set. First is the MEP-004A. That's what you have. There is a throttle cable that attaches to the back side of the roosa master fuel pump that controls engine speed, (that equates to frequency) of the set.

The next application is the MEP-103A (Precise Power) set, that uses an electronic governor and actuator. It attaches to the lever in question.

The third is the MEP-113A, the 400 hertz model, that uses the governor and actuator method of engine control. So, as long as you do not have a governor and actuator control, nothing gets attached to the lever. No problemo!!