MEP 531A Fix-up Thread

[CallMeColt]

Howdy all,

Been a while since I started one of these!



Got myself a MEP 531A at auction. Definitely had a bunch of hands in it, but, I got one of the best deals that was had in a while on one.

I knew right away the breaker was pushed into the panel and the cover over the gauges was missing.

Replaced some fuel lines, a few fuel tank fittings, hose clamps, and put in some missing bolts at the alternator that held it to the bracket. Checked to be sure the governor fork was correctly on the injection pump via the inspection window. Added some 15W-40 Rotella T4 and diesel. Took the slave cable out of my M1078 & cranked for about 20 seconds, got nothing. Found the clamp at the injection pump loose. Tightened and it fired right up!

Gave it a little while to finish purging the air while I put away the cable.

Nothing at the gauges. Breaker was tripped. Found a broken wire at the breaker. Made a quick jumper to test. Still nothing. Fuse at panel okay. Fuse holder okay.

After some reading, decided the flash the alternator. Boy, the TM is not great at explaining this! Took me like 4 hours to figure out where this needs to be done. I made a video on it;

After flashing for about 15 seconds, breaker stopped tripping. Nothing on the gauges though.

I'm getting ~ 15 volts AC at 8 & 9 on TB-1. There is nothing covering this in the TM. Flashed a couple more times with no different results. Tried searching and nothing came up for results. Any ideas group?

 

[WWRD99]

Mines still sitting, has been pretty much since I got it...never could figure out which ones to flash so it's been yard art since...I'll give this a try and see if I can get something out of it.

 

[CallMeColt]

Mines still sitting, has been pretty much since I got it...never could figure out which ones to flash so it's been yard art since...I'll give this a try and see if I can get something out of it.

If I don't get this unit to make power, I'll just part it out and use the motor on something else. That was my backup plan.

Hopefully you get yours going!

 

[WWRD99]

If I don't get this unit to make power, I'll just part it out and use the motor on something else. That was my backup plan.

Hopefully you get yours going!

It runs perfectly just does the no breaker thing and won't make power...I've tried the drill thing and thought I did the flash but I used a 9 volt battery...it did nothing...thought that the diode going to the breaker was burned out so I cut it out thinking it was bad but then it tested fine then I lost it...I need another diode lol...just hasn't been a priority since I power the house with an 803...don't need it. Too loud to go camping with too...I even welded a car muffler on it...needs a box. Thanks for the video though...I'll do the 12 volt battery next time.

Sent from my SM-G975U using Tapatalk

 

[GopherHill]

On YouTube there is James Condon who works on generators. He has good testing and troubleshooting information.

 

[CallMeColt]

It runs perfectly just does the no breaker thing and won't make power...I've tried the drill thing and thought I did the flash but I used a 9 volt battery...it did nothing...thought that the diode going to the breaker was burned out so I cut it out thinking it was bad but then it tested fine then I lost it...I need another diode lol...just hasn't been a priority since I power the house with an 803...don't need it. Too loud to go camping with too...I even welded a car muffler on it...needs a box. Thanks for the video though...I'll do the 12 volt battery next time.

Sent from my SM-G975U using Tapatalk

I put a new diode in just in case, I had a bunch. Send me a PM with your address.

 

[CallMeColt]

On YouTube there is James Condon who works on generators. He has good testing and troubleshooting information.

I have actually seen his videos and watch them in the past for other things. Unfortunately, I don't think his will be helpful on these units because they're unique to the MEP 531A. I think I have a bad alternator or voltage regulator at this point.

Funny, I saw where you are from... I grew up in Thomaston, CT and Thomaston, TX isn't that far away from me.

 

[WWRD99]

I put a new diode in just in case, I had a bunch. Send me a PM with your address.

That's funny you know where the one I'm talking about is...I was ready to try anything!! I remember when I thought it was bad I looked up replacements and found a bunch but had to buy like 10 at a time for like 8$ and for some reason I never bought them!

 

[CallMeColt]

Well, this may end up being a short fix-up thread.

Went through the alternator testing procedure as per the TM via P1, E & F. Resistance should be 13-16 ohm. I got 37.6... way off. I know temperature can effect this and it drift a bit, but not that much.


Also tested the stator via P1, started with A & B. Should be 0.7 to -1.0. I got 1.0 to 0.9.... kept bouncing around. High but a little closer and within some of the drift I have seen with the higher temperatures when taking these readings.


Someone has had the generator head apart before, I assumed during the new motor install... maybe not. Debating if it is worth putting more time into it or just gutting it. I'd be happy to use the motor on my diesel mini bike project. Just don't want to sink money into it. The rest of the parts look good, test them and sell them to put into something else.

I will wait a while though in case someone else chimes in with a solution I'm not seeing here!

 

[WWRD99]

Well, this may end up being a short fix-up thread.

Went through the alternator testing procedure as per the TM via P1, E & F. Resistance should be 13-16 ohm. I got 37.6... way off. I know temperature can effect this and it drift a bit, but not that much.
View attachment 865698

Also tested the stator via P1, started with A & B. Should be 0.7 to -1.0. I got 1.0 to 0.9.... kept bouncing around. High but a little closer and within some of the drift I have seen with the higher temperatures when taking these readings.
View attachment 865697

Someone has had the generator head apart before, I assumed during the new motor install... maybe not. Debating if it is worth putting more time into it or just gutting it. I'd be happy to use the motor on my diesel mini bike project. Just don't want to sink money into it. The rest of the parts look good, test them and sell them to put into something else.

I will wait a while though in case someone else chimes in with a solution I'm not seeing here!

I didn't look up the procedure on the test but did you have to remove or at least put something in between the brushes before the test to take them out of the equation or do you leave them in contact. That could change the number that big being it's more than double from what it should be. The temp swing would have to be pretty big to get that number too.

 

[CallMeColt]

I didn't look up the procedure on the test but did you have to remove or at least put something in between the brushes before the test to take them out of the equation or do you leave them in contact. That could change the number that big being it's more than double from what it should be. The temp swing would have to be pretty big to get that number too.

The TM has you do it first exactly as I have it pictured. If it is not within range, then remove everything to confirm... but, it seems that if you remove it that you will more than likely get the same reading, and it is just removed so it's ready to be replaced. Unless you find something like a shorted/broken wire along the way.

 

[CallMeColt]

I pulled the control panel and alternator cover off to have a look inside. It all looks neat and in order but someone was in there.

Some of the caps to the brushes seemed loose to I tightened and tested again... less than 1 volt now with the breaker not tripping. It must be toast.

I guess it will be a parts machine! Motor and fuel system will go to the mini bike project, alternator and frame to the scrap, and some of the stuff from the panel I will manually test down the road and save or sell.

 

[CallMeColt]

I'm taking this thing apart today and am a bit stumped on how to take the generator off. TM is useless. Work Package just says "Remove from Engine" Uhhh, okay. They will write 3 pages on how to change a hose clamp, but not elaberate on how to do this. So government!

 

[CallMeColt]

Turns out, you just keep tapping on the housing and it will come off from the adapter plate bolted to the motor.

The stator made ever so slight contact at some point... probably why it wasn't making power. I didn't take pictures at the time but if I didn't already get rid of it, I will edit the post to show it.

Motor is all ready for the mini-bike build. Going to take the good parts that I can and list them on my store.

If by chance anyone reads this in a reasonable amount of time from me making this post, let me know if there is a part you need and we can work something out.

 

[FarmingSmallKubota]

not sure if its too late, but i sure could use that air filter cover the front door and those black knobs that hold the covers in place. very unique can not find it anywhere.

 

[CallMeColt]

not sure if its too late, but i sure could use that air filter cover the front door and those black knobs that hold the covers in place. very unique can not find it anywhere.

It's not to late, reach out to me via PM. Sorry on the late response. I was away on a road trip.

 

[CallMeColt]

I wanted to revive this old thread in case anyone is still watching.

I kept some of the parts when I parted this out. One of the was the potentiometer for the voltage adjustment. I grabbed it from my parts bin to use on something & went to use it with no luck. Tested it, and it was dead! Basically no reading (open) across almost the whole range.

So, I am thinking.... could the issue with this generator have been this the whole time? If the POT was bad, it would have made the voltage adjustment call way off, and made the regulator put out bad AC voltage as well.

I just HAD to come back when all this came racing back into my head. Kinda disappointed if this is the case, but, someone else can hopefully learn from my mistake hopefully.

I just got 2 more of these generators & they are in great shape with really low hours. They don't need anything except fuel lines, filter, & fuel! So, I'll be learning about them again.

 

[WWRD99]

I wanted to revive this old thread in case anyone is still watching.

I kept some of the parts when I parted this out. One of the was the potentiometer for the voltage adjustment. I grabbed it from my parts bin to use on something & went to use it with no luck. Tested it, and it was dead! Basically no reading (open) across almost the whole range.

So, I am thinking.... could the issue with this generator have been this the whole time? If the POT was bad, it would have made the voltage adjustment call way off, and made the regulator put out bad AC voltage as well.

I just HAD to come back when all this came racing back into my head. Kinda disappointed if this is the case, but, someone else can hopefully learn from my mistake hopefully.

I just got 2 more of these generators & they are in great shape with really low hours. They don't need anything except fuel lines, filter, & fuel! So, I'll be learning about them again.

Dang I may have to check that on mine since it just spins easily without stopping!! I still need that diode lol....haven't touched that set in a long time!! Might have to give a little more testing on it!! I have been watching a ton of these on sale in New Jersey next week so I may end up with another too.

 

[Icesythe7]

@CallMeColt released a new video!

 

[WWRD99]

@CallMeColt released a new video!

Just watched it. They are fun to get primed! I did mine pull start though since I didn't have a slave cable yet.

Sent from my SM-S906U using Tapatalk