MEP-018A Won't Shut Off

[rebel_raider]

First off let me say that I have searched this forum and also SmokStak and I have not found any instance of what I'm experiencing. I can get my generator started, but I can not shut it off with the normal stop switch or the emergency stop switch. I checked the K1 thru K4 relays according to the TM and they check good. Has anyone else experienced this? I'll also add that the remote stop switch does not kill the engine either. When I place the normal stop switch in the stop position I can hear a relay click. Surely I'm not the only one to experience this.

Also, how might I rig up a timing light for this engine? Or should I not worry about it and time it by ear?

 

[Guyfang]

Is this gen set new to you?
Have you seen it run right before?
why do you need to time it?
do you have the TM's?
when you follow the instructions in the TM on timing the Magneto to the engine, you are very close to perfict. If it's still not quite right, the adjustment is simple. Loosen op the mag and move it up or down a bit. We could used a army timing light, made for this type of gear and shined the light on the timing mark. But normally we timed by ear.
The first thing I would look at is the fuel cutoff solenoid. It is mounted under and to the side of the carb. When you flip S1 to the off position, it cuts off the voltage to the solenoid and in retracts, causing the carb to go to no fuel position. There should be a rubber cover on top of the solenoid. Remove it, and make sure the solenoid travels up and down. Then, start it up, and measure on the solenoid terminals to see if it has 24 volts. Shut off the set, it's best to have a helper, while you measure the voltage at the solinoid. If the voltage is present after turning off S1, then it's a stuck relay. I could explain more with my manuals, but am not home, and texting while driving cost about 100 bucks here. When I get home, will look at the TM's

 

[rebel_raider]

This set is new to me. I had to take the magneto off and clean the points up. I did reinstall the magneto at the same position, but it has a "hiccup." I do have both TMs for the generator and both for the engine. I thought the round solenoid with the rubber cover on top was the choke solenoid?

 

[Guyfang]

There is a lever, on the side of the carb for choke. I am still not home, but will review the manuals when I get home. I have seen this problem before, but it was always the relay. It's also been 35-40 years since I worked on this set.

 

[Guyfang]

Excuse me. I stand corrected!!!!!!!!!!

You are correct. It is the choke solenoid. And the start switch is S4, not S1. This happens when I go from memory, 35-40 years here.

Relay K2 is the stop relay. In TM 5-6115-275-14, PDF reader page 218, there is a description of how the stop function works.

(2) Relay K2 is used to stop the engine. The relay is energized by the S I stop switch and S5 Remote Local switch. When relay K2 is energized, relays K3 and K 4 Are de-energized, thereby removing the battery charger from the circuit and grounding the magneto through the normally closed contacts of relay K4.(3) Relay K3 is energized by the battery charger rectifier through the normally closed contacts of K 4. and de-energized by low oil pressure.(4) Relay K4 is energized through the normally closed contacts of relay K2 and the silicon diode, CRI.This occurs when start and stop switch, S1, is activated.(5) The relays are identical and interchangeable

You said you tested the relays. How? You also need to test CRI, as its a blocking diode. If its bad, then the relay, (K2) stays energised.

 

[rebel_raider]

Paragraph 4-43 (page 161) in TM 5-6115-275-14 describes the coils of those relays should have a resistance of 300 ohms. Two of my relays were 297-298 and the other two were 288-289. I energized the coils of all relays and checked the NO and NC contacts. I did miss the paragraph you quoted. That would have saved me a lot of headache and head scratching this morning. I have not checked the diode.

 

[rebel_raider]

Well thanks to Guyfang for pointing me in the direction of diode CR1. I tested it and was allowing current to flow both ways thereby keeping relay K2 energized. I'll see if I can order a diode and get that fixed and then see if that solves anything.

 

[Guyfang]

Well, glad you found the problem!

Just get a diode. Easy to replace.

You know, I spent the first two years working on this set, mostly at 02:30 in the morning with a army "L" flash light gripped in my mouth, (yes, people have told me I have a big mouth, and one fella even shut it for me) in the rain or freezing cold. I still have a soft spot for it. Kinda nice to help you on it. On one side, 1973 was a long time ago. on the other, a blink of the eye. I always liked the sound of the starter turning the MEP-018A over.

Take care and let me know how you do.

 

[rebel_raider]

I'll update when I get the diode replaced. Thanks again for your help.

 

[rebel_raider]

Well according to an electronics guru, my diode is good. I guess I need to brush up a little bit. So now I'm back to chasing wires. Surely I didn't hook up the wires wrong in the magneto. Or maybe the ground wire to the magneto has a break in it although I called myself checking that. I'm probably overcomplicating this like I do everything else.

 

[Guyfang]

Mesure on the relays A1 and A2 coil, while running. Then hold the probs there while someone turns off the S4. See if you loose voltage. Because if the magneto gets grounded, like what SHOULD happen, then it has to stop running.

 

[Guyfang]

Had any time to look at this set?

 

[rebel_raider]

I think I've tracked down the problem, but I'm going to wait until I fix what I think it is before I report back. I have traced many wires and checked the relays again, and I think I finally found it. Hope I didn't jinx myself.

 

[Recovry4x4]

They do have a semi unique sound albeit loud. There is a 3KW MEP016 at the FL Rally site used to power the field shower. It's smaller but still a flat 4. You can hear it at camp 200 yards away.

 

[rebel_raider]

Yeah I may have to build a privacy wall of some kind to park it behind if I ever need to use it for an extended time. Although at the rate it consumes fuel I don't think I'll have to worry about that too much.

 

[Guyfang]

After you spend a few years sleeping every 2-3 nights next to one of them running, it's hard to sleep without the sound of them running!

 

[combat32]

Where did you pick up the 18a Conrad, I've owned a couple but sold and upgraded to mep 002

How's the rest of the El Dorado gang?

 

[rebel_raider]

We're good Tom. How are things in your neck of the woods? I picked it up from a guy I did some work for. Actually bought a gin pole truck off of him and he said "I think I've got something else you may be interested in."

Now for my next question: Is the S2 toggle switch a "divided" switch? That is, is the right side of the switch not connected to the left side. I thought I had a bad switch and replaced it with an off the shelf on-off-on toggle switch and now it won't start. I have checked resistance between the negative battery cable and the contacts of switch S1. Less than an ohm of resistance between battery cable and common of S1. Meter shows open between battery cable and start terminal of S1 when in start position. Meter also shows less than an ohm of resistance between common and start terminal of S1 when in start position.

 

[combat32]

All good here, headed to Greenbrier Wednesday to pick up another mep-016 I bought, guess I can't get enough generators.

Not sure about your switchology problem, that is a new one on me. Saturn Surplus may have the correct switch to replace it.

I no longer own a mep-018 to to look at and tell you. Ron from our club has two, I sold him my last one, you might try contacting him through the club website, one of his is a spare parts set he might be able to help you out. I have his e-mail if you want it send me a pm.

 

[rebel_raider]

Ok thanks. I may do that. I actually won one from Greenbrier myself. I've got several things I need to order from Saturn, but I was trying to wait and see if I needed anything else so I could order all at once. Although I may not need to once I get my spare set home. I'll just have to wait and see.