MEP-831a Troubleshooting

If I was working under a schedule I would for sure do that. Since I'm unemployed and otherwise bored, tinkering on the generator the last couple of days has been a welcome project to concentrate on.

I really appreciate all the great info.

Do you know of any trouble spots to keep an eye on with these generators or recommend any spare parts to keep on hand?

I have to figure out a battery solution for this thing.

I'm going to use 2 motorcycle batteries myself.

Have you figured out which size will be best?

Not yet ,mine are still not here. but after looking at the battery box. looks like there is plenty of room for using 2.

The battery is smaller than I expected. I went to WalMart yesterday and test fit a number of batteries. I could get pretty close but I didn't find a combination I really liked.

I'm thinking about a pair of these - http://www.amazon.com/YT14B-BS-High...1422021280&sr=8-3&keywords=motorcycle+battery

From the measurements it looks like they will fit.

How big is the battery box. Looking at pictures I have seen it looks pretty big. But unfortunately mine are not here to measure.

Here are some crappy cellphone pics of the battery and battery tray. There is plenty of room to go taller with the battery.

so is the battery roughly 7 inches square?

It is just a tad over that, I'd call it 7-3/8ths. The battery fits snug enough that once you put it in there it won't fall off.

I found a drawing for the battery that has the exact dimensions. I also found a reference source that has a lot of battery sizing info. I'm looking through that to see if there is something of interest.

The battery reference doesn't include many of the motorcycle batteries. So far one of the best fits I've found is for the one I posted the link from Amazon. I may go ahead and order a set of those and see how they work.

the next bigger size will fit also YT16B-BS

I just went through the batteries on Yuasa's battery chart and it looks like a pair of YTX20L-BS is the largest battery that will fit.

Dimensions: 6.875" x 3.4375" x 6.125"

The 20s are great ! I use them on my 4 wheeler and my Harley uses that size to !

I am going to drop in a pair of those batteries and see how it works. I went out this morning and started it for kicks. It took 3 pulls f it to light off. Easier than my push mower. Maybe I should put a yanmar diesel on that!?

Update for today. The replacement connector body for J7 arrived today and I transferred all the pins from the old one to the new one. I replaced the pin for the B+ lead and dropped into the connector. Checked continuity and off it went. One problem down. Since I didn't have a crimper I decided to solder the wire. I know its not the best practice to do in a high vibration application. I'll cross my fingers that the solder joint doesn't fail. The new pins had a strain relief so I did get a good crimp on that which should help take the pressure off the solder a bit.

I checked on the fuel sender. When I peaked at it through the top I could see 3 wires landed on the center stud. There should have been only one. I took them off and isolated the wire that went to the gauge and put it on the post. I landed the other two wires under one of the screws for the fuel sender. The fuel level gauge now works.

I tweaked the magnet on the speed control arm a little bit so it would shut down more reliably. About half the time as it was shutting down the magnet would release the arm and it would just idle really low without shutting down.

Getting closer.

How did you tweak the magnet?
There is a very specific adjustment procedure for the governing system on these sets.
If the adjustments aren't made properly then the variable speed concept of these sets will be no good.
The speed increases with load so the more load you have the faster the engine turns.
The procedure is in the TM, if you don't have the TM I could send you a copy of the governing system procedure.
If you maladjusted the magnet then the procedure will do you no good and you wont get the full benefits of the variable speed concept of the set.

That would be great. I've found the operating manuals online for it but I've not found a real technical manual with setup procedures.

There are some many little things that seem to be off on this unit I has made me wonder if it was put together this way as some kind of a training system to test technicians on how to troubleshoot and repair them.

My goal is to have it running as close to specification as possible.

I can bet most of the people that have these sets don't have the variable speed setup properly.
If you didn't adjust the magnet it self then I can help, but if you adjusted the magnet then I can't.
I'll dig out the procedure later today and send to you.
Do you have a source of 3 kW load?

If you don't have the governing system set up properly then you wont get the full benefits of the set (fuel consumption, wear and tear on the engine, maintenance and such)