MEP-831a Another 1st Time Buyer & Fix (K1 Relay Contactor)

[mk2000]

Hi first post, here. Lurking for several months and recent MEP-831a owner. Thanks to Guyfang,Dewie38, DieselAddict & kloppk for the education. I’ll break this post up to make it more readable.
Received the genset and ordered new batteries (BatterySharks STX20-BS, QTY 2), air filter (AmazonX0018PGME5),fuel filters (Wix 33046,QTY2) fuel separator (Wix 33583).

https://www.batterysharks.com/SigmasTek-STX20-BS-p/stx20-bs_m12-19-270-hd.htm
https://www.amazon.com/Air-Filter-Combo-Yanmar-L40/dp/B01M5FQY55
https://www.amazon.com/WIX-Filters-Complete-Line-Filter/dp/B000C9XZ0G
https://www.amazon.com/WIX-Filters-33583-Heavy-Separator/dp/B01LRHO0BE

Inspection finds:
275 hours on the clock
TB4 High Voltage cover off
Inverter connector 6way J-16 unplugged
Missing fuel cap

 

[mk2000]

Thought I had an oil pressure issue....
Change the oil, clean the oil screen (it was clean) changed filters, add fuel, install batteries and it started right up. Ran for about 15 seconds and then I shut it off to look for any issues/ leaks. I restarted and ran for about a minute then noticed the low oil pressure light was on and the engine would not turn off by the Run/Stop switch – I had to manually pull the governor arm to stop it. I removed the oil press switch and checked it with compressed air… and it switched open OK at > ~14 psi. I checked the running oil pressure with a gage and found it OK at 74PSI.

I have found through reading the forums that you must hold the start switch in “crank” for minimum of 2? seconds. Using this start method I have no faults, oil pressure or otherwise, and it with now shuts down properly with the Run/Stop switch.

Wish I could cite that reference here in Steel Soldiers (spent hours trying to locate the thread).

 

[mk2000]

Found an electrical issue:
Now that it starts and runs I connected a few appliances to the convenience outlet, makes 120V 60hz and governor appears to adjust engine speed as electrical load changes. Unfortunately, now I found I have zero volts at the output load terminals when I activate the Circuit Interrupter switch.
I first verified the K12 and K14 were 24V and bench checked their function.
I then verified the K15 was 120V and also bench checked.

I tried to follow the field level trouble shooting in the manual, steps 13 & 14… but I got hung up on step 14b (on page 132) where it has you check resistance between S5-2 and TP31 on TB3, “reading should be 0 ohms”. In the next column for corrective action itstates “If voltage is 0 VDC”… I wasn’t sure at this point if they were checking for a resistance or a voltage. I knew the gist of the exercise was to verify the K1 relay coil was receiving the ground signal. I had BAT voltage at the K1 term 1.
I traced the entire ground path from:
TB5 15a
to
K12 relay Term 12
to
K12 relay Term 4 (normally closed relay)
to
K15 relay Term 12
to
K15 relay Term 8 (normally open relay)
to
Battle Short Term 9 and J7(10)
to
P7(10)
to
P17(12)
to
K8 relay (normally closed) within inverter A8
to
P17(11)
to
P7(9)
to
J7(9)
to
BattleShort Term 8
to
S5 Term 5(AC Interupter Switch) and Hour Meter
to
S5 Term 2
to
TB5-8A
to
J7 (29)
to
P7 (29)
.. andfinally
K1 Term 2


I could apply 24V across K1 coil and hear a faint click.
I removed the relay and while bench checking it I found the contactor remained open despite hearing the relay click. I wrapped the relay on the bench and could hear the plunger free-up. I opened the relay and found a light, white fuzz on the plunger. Since it was otherwise absolutely spotless inside, I wiped the plunger with WD40 and re-assembled. No longer a faint click, but a solid sound of the contactor movement. I slotted the tabs of the relay bracket so the bolts could be pre-started to ease assembly.

I fired it up and now have voltage at the output load terminals when the AC Interrupter is activated!

 

[Guyfang]

Good post. Good work. Pictures did not come out and please do not post anything written in blue. You cant see it on the green background. The info you posted is very good, but no one can see the links. Please re-post the pictures. The fuzz, I have seen before, but long time ago. Its not a big problem, if it doesn't sit for years. Then its harder to clean up. Good job!

 

[stugpanzer]

Welcome to the forums and to the addiction! Great detailed post!

 

[mk2000]

MEP-831a Replacement fuel cap

I could not source a fuel cap that was reasonably priced, or find a cross-reference from the auto parts store.

$500 dollar solution:

ASAP NSN Parts
NSN Number : 5342011987569
Manufacturer : Honeywell Lebow Products
Part Number : 98-19516
Quantity Min- 2
Price- $250 each
Delivery- Immediate
Condition- New

$10 "+" dollar solution:

Then I noticed the fuel cap on my FarmAll tractor looked darn close. The innards were similar but a few thou oversized in diameter. I bought a $10 replacement cap IHS226 (Steiner Tractor) and a few hours of massaging, I had a nice fitting fuel cap for the MEP-831. I do value my time more than that, but was already invested into trying an alternative.

https://www.steinertractor.com/IHS2...s-buy-clean-fuel--keep-it-clean-like-original