MEP-002A Exhaust Question plus Machine Resurrection

[Tinstar]

Ok

Cleaned S7 contacts and made no difference.

Hooked up multimeter to starter solenoid for first start.

All went normal and solenoid received 24v for starting.
Ran unit for about 45 minutes.
Nice and cool this morning so it took a bit to get hot.

Shutdown engine and immediately tried restarting.
Same thing as before except this time no power to solenoid.
Nothing…….

I’m familiar with starter solenoids working or they don’t. Not dependent on temperature
Tapping in it with hammer has zero effect.
Verified S7 contacts are closed when I saw no power to solenoid.

Gotta do some reading.
Clearly I’m missing something.

 

[rickf]

Personally I would start tracing that solenoid wire back from the starter solenoid and see where it leads me. Between that and the TM's you should be able to find the problem easily enough. Every time you find a connection point in that wire take it apart, clean it and check it for power afterwards until you find the one that has power on one side and none on the other and then you have found the problem. To verify wait for it to cool off and see if you now have power at that point.

 

[Tinstar]

That’s exactly what I’m doing right now.




Cleaned off the outside of the stainless steel battery hold downs.
They should be here Wednesday.

 

[Tinstar]

FOUND IT!!!
Traced the wire to the rear of control panel.
The K3 Crank Solenoid is bad.
K2 is the preheat solenoid.

The bottom wire of K3 is always hot with battery voltage.
Once you switch the selector to the crank position, the top wire is (supposed) energized and sends power to the starter solenoid.

This one does not.
I made a jumper wire and it cranks and starts just fine.


Will be seeing if I can take this one apart and clean it.
If not, another for the parts cannon.

 

[rickf]

Strange that heat would affect that but like I said, wait until it cools down and see if it passes the test when cool. Those relays appear to be able to be disassembled. I would take all the wire off and brush those small studs clean and put some Kroil or WD-40 on them and remove the cover and see if it is just dirty or corroded inside. Cheaper than firing that parts cannon again. LOL.

 

[Tinstar]

Looks fine inside

Will clean contacts up and reinstall.

 

[Tinstar]

Relay is bad
Took apart and cleaned contacts.
Same issue.
Swapped with K2 relay and problem followed to the preheat circuit.
Took cover off relay and applied power.
Bad relay gets power. But doesn’t move at all.

Time to go shopping

Guess the heat was just a coincidence.

Gonna run it for a while to make sure.

 

[Tinstar]

I’m SO glad it wasn’t the S7 switch.
I was really dreading the possibility of having to replace that.

Edit:
Found a NOS one, Eaton brand.
MS24166-D1
They’re Not cheap.
Mostly used in Aviation so that explains the price.

 

[Tinstar]

Hold the phone

Unit nice and hot and STILL doing it.
Both relays have power to them but power not going to top post when switch turned to crank.

I’m at a loss for now.
Time for a drink

I still think relay was bad since it’s not working for preheating now.
I can jump the K 3 and engine will start so it’s not the solenoid.
No powder to solenoid when attempting to crank.

15A fuse at S7 switch is still good.

Time To study the schematic

 

[Guyfang]

In case you still want to order a relay, the orig. NSN, 5945-00-686-6877, is the prime NSN, but the following NSN's, are also compatible:

5945-00-601-2141
5945-00-602-6806
5945-00-901-1766
5945-00-907-3215

And the Prime Part # MS24166D1 can also be replaced by the part #'s on the left side of this listing. The right side numbers are the CAGE code.

11697809	02731
283A425P1	1DUQ5
283A425P1	01526
307-0959	44940
307P959	44940
5945006866877	SCY13
5M.4759.220.57	D1901
6041-H200	27192
6041H200	81640
6416017	001JK
6416017	S4956
7064-4653	D0080
7064-4653	58657
825RL0082	A0199
EE36972	45152
GHN20017-001	98897
MIL-PRF-6106	81349
MIL-R-6106	81349
MS24166-D1	96906
MS241660D1	96906
Z00.N7733062466TBM	F0086

 

[Tinstar]

WOW

That’s quite the post.
Tons of great information.
Thank you

I jumped on eBay and found a brand new Eaton exact replacement.

 

[Guyfang]

Make a jumper wire. Go from TB4-10 to K3-X1. Try and start it. Try 10-15 times, if it starts, just to be sure.
If it wont start, move your jumper to K3-X2 to TB4-12. Same drill

 

[Tinstar]

[QUOTE

Make a jumper wire. Go from TB4-10 to K3-X1. Try and start it. Try 10-15 times, if it starts, just to be sure.
If it wont start, move your jumper to K3-X2 to TB4-12. Same drill

Looking behind the control panel this morning to make sure I’m clear exactly where to connect jumper wire, I noticed this.


Doesn’t appear to have rubbed completely through, but it was getting there.
I placed a 1/8” thick piece of rubber underneath it for now until I properly repair it with shrink sleeve.

Will do the jumpers later today.

 

[rickf]

On that relay look for where the connection wires connect to that coil and with the relay disconnected from the circuit do an ohms test across the coil. If open circuit that is the problem, if not it may still be the problem. Heat it up with a hair dryer and check while heating. If it never opens keep it as a spare since it is not bad. If it does open then look closely at the wires where they connect to the terminals, especially if they are soldered. These machines vibrate like nothing else and solder joints will work harden and crack. With an expensive relay if it can be resoldered and put back in service that is money that can be better spent elsewhere.

 

[Tinstar]

Make a jumper wire. Go from TB4-10 to K3-X1. Try and start it. Try 10-15 times, if it starts, just to be sure.
If it wont start, move your jumper to K3-X2 to TB4-12. Same drill

Ok
Did the first jumper sequence and no luck

The second one, K3-X2 to TB4-12, worked
Cranks and starts right up.


I can’t follow the schematic well enough to know why this worked.

 

[Guyfang]

OK. The reason your K3 will not close is because you do not have a path to ground.

You jumped from TB4-10, On wire #P57B to A1-5, Through CR1, to A1-6, through wire #P58A to K3-X1.

And it did not start. So your problem can not be here.

Then you jumped from K3-X2 to TB4-12. And it started. So, the problem is between the K3-X2 and TB4-12.

So now jump from K3-x2 to TB4-3. What happens?
Then jump from TB4-3 to TB4-12. What happens?

 

[Tinstar]

Ok
I will check


My head hurts

 

[Guyfang]

Beer helps. Or listen to Paul Horn's Inside LP. Then beer.

 

[rickf]

Remember what I said WAY back somewhere in this thread about electrical problems? Start with the grounds and then the connections. I followed that up with proper diagnostics will solve the problems where throwing parts at it will just cost money and aggravate the problems. A lot to be learned here. Don't get frustrated, you are in the learning phase. AND, especially this, you are actually listening to these guys who are actual experts on this stuff,

That not only helps you out immensely but it also gives you a very high standing with the community here! You have no idea how many times we try to help people and they either say they will do what we ask and then do something else or they simply disappear after probably doing what was asked and fixing the problem but never thanking anyone.

 

[Tinstar]

View attachment 898229
OK. The reason your K3 will not close is because you do not have a path to ground.

You jumped from TB4-10, On wire #P57B to A1-5, Through CR1, to A1-6, through wire #P58A to K3-X1.

And it did not start. So your problem can not be here.

Then you jumped from K3-X2 to TB4-12. And it started. So, the problem is between the K3-X2 and TB4-12.

So now jump from K3-x2 to TB4-3. What happens?
Then jump from TB4-3 to TB4-12. What happens?

K3-X2 to TB4-3 did nothing.

TB4-3 to TB4-12 cranked and started