MEP-003 - Not engaging Starter

[chiefgguy]

Team SS!

I find myself again needing some guidance to getting my MEP back up and running .. The unit has been running great for the past several years, we use it predominately on weekends to run an off-grid cabin.

I've reviewed several the threads on the site and have tried some of the steps but still no joy..

About 3 weeks back, we ran into an issue where it would not "start" by that I mean the starter is not "engaging" to turn over the unit. There is a mechanical "click" from the right of the unit where the plunger engages under the solenoid, beyond that there is no further "noise" or "action". We've taken the following actions:

- Checked the batteries they test good, but went ahead and charged them up while we had them out.
- Checked the starter solenoid/starter - we can short a screw drive across and it "functions"
-Checked power at the solenoid for the fuel shutoff and we have power there (the plunger does actuate when we try and start)
- took the cover off the starter lockout (just below the fuel solenoid) and it remarkably clean in there.

Today we setup a manual switch connected to the solenoid / starter, and manually press the plunger up (on right under fuel solenoid) and we can get the unit to run (although I have manually to continue working the plunger). Once I let go of the plunger the unit stops.

We think it's a power problem since we can get the unit to start, but not sure how to further diagnose. Any suggestions or ideas are welcome!

thanks - Andy

 

[212sparky]

Is it starter solenoid on the starter that engages the bendix and sends power to the motor that is the problem or the fuel shut off?

Sent from my SM-N960U using Tapatalk

 

[chiefgguy]

Is it starter solenoid on the starter that engages the bendix and sends power to the motor that is the problem or the fuel shut off?

Sent from my SM-N960U using Tapatalk

Not sure, I'm assuming the fuel shutoff has to be functioning to compete the circuit to have power at the exciter on the solenoid. But I may not be stating that correctly

 

[Ray70]

I should probably check the schematic before making this statement BUT.... I don't recall the fuel solenoid having anything to do with the starter circuit.
The speed switch under the oval shaped cover near the oil filter is the mail culprit if you don't get power to your starter solenoid. It's function is to disengage the starter after the unit starts to allow you to continue to hold the switch ( without the starter continuing to crank ) in the crank position until oil pressure closes the oil safety switch.
The click you hear is probably the fuel solenoid, but I would double check the schematic before assuming that has anything to do with the starter circuit.

 

[Guyfang]

I should probably check the schematic before making this statement BUT.... I don't recall the fuel solenoid having anything to do with the starter circuit. (Correct)
The speed switch, (S7) under the oval shaped cover near the oil filter is the mail culprit if you don't get power to your starter solenoid. It's function is to disengage the starter after the unit starts to allow you to continue to hold the switch ( without the starter continuing to crank ) in the crank position until oil pressure closes the oil safety switch. (Test procedure is in the TM, and its an easy test to do.)
The click you hear is probably the fuel solenoid, but I would double check the schematic before assuming that has anything to do with the starter circuit. (The starter circuit and fuel sol. nothing in common). Perhaps the adjusted wire diagram will help you.

Open to see comments.

 

[chiefgguy]

Open to see comments.

Apologies for the delays, the weather hasn't been the most cooperative around here! @Guyfang thank you for the highlighted drawing this is helpful!! On saturday as I was getting ready to start tracing wires and really dig into diagnosing what's happening, the darn thing started and ran like a champ!! closed it up put my tools away and knew this wasn't a good thing but didn't know what else to do! Today (Sunday) thought I would give it a try and back to the same problem. So clearly some type of intermittent problem!!

Here's some things we tried today:

- we thought K3 might be problematic, so we switched it with K2 and had the same result. We don't see power at the top lug of K3 when trying the start position. We do see 24V on the bottom most lug

- We do see power at K1 - A1-1 (start position)

In doing some further review of the previous attached drawing, I see i missed some of the comments regarding S7 (Starter Disc. Switch)

The hunt continues and thanks for the input so far!

If anyone in N. Houston, TX is reading this and would be interested in helping?!!!

andy

 

[Guyfang]

Apologies for the delays, the weather hasn't been the most cooperative around here! @Guyfang thank you for the highlighted drawing this is helpful!! On saturday as I was getting ready to start tracing wires and really dig into diagnosing what's happening, the darn thing started and ran like a champ!! closed it up put my tools away and knew this wasn't a good thing but didn't know what else to do! Today (Sunday) thought I would give it a try and back to the same problem. So clearly some type of intermittent problem!!

Here's some things we tried today:

- we thought K3 might be problematic, so we switched it with K2 and had the same result. We don't see power at the top lug of K3 (whats the wire number) when trying the start position. We do see 24V on the bottom most lug

- We do see power at K1 - A1-1 (start position)

In doing some further review of the previous attached drawing, I see i missed some of the comments regarding S7 (Starter Disc. Switch)

The hunt continues and thanks for the input so far!

If anyone in N. Houston, TX is reading this and would be interested in helping?!!!

andy

open to see comment.

 

[chiefgguy]

open to see comment.

Between raining days, a day job and honeybee's that needed some attention! We are making some progress .. I'm confident that the problem is in the Starter Lockout Switch .. When the unit will not engage the starter, if I disconnect the barrel connector and short those wires together it will engage the starter. However, it's is persnickity as some days you walk up and it will fire right up. sometimes in the same day you can get different results. The only thing changing is the temp/humidity as no other actions are taking place on the generator, and it's covered wiht a tarp!

When I measure the continuity, before starting, of the metal plate across the plunger measures correctly. While running I can see in the measurement that the circuit then opens. I'm guessing that the plunger under this metal "strap" is the culprit and it's right on the razors edge of some kind of problem. My next step is pull the Lockoutswitch (already removed front shroud) and visually inspect and see if there is someting obvious. I need to review the TM, but i'm wondering if slightly "sanding" the plunger "nipple" would be sufficient? It seems that whatever is wrong is ever so slight and that the humidity/temp is just enough to push it one way or the other..

 

[Guyfang]

Between raining days, a day job and honeybee's that needed some attention! We are making some progress .. I'm confident that the problem is in the Starter Lockout Switch .. When the unit will not engage the starter, if I disconnect the barrel connector and short those wires together it will engage the starter. However, it's is persnickity as some days you walk up and it will fire right up. sometimes in the same day you can get different results. The only thing changing is the temp/humidity as no other actions are taking place on the generator, and it's covered wiht a tarp! (Well. It could be anything shown in the picture. BUT its probaly S7. Take it out and look at it. It is simple and easy to pull out. Make sure nothing is bent. If its good, follow the TM instructions on reinstalling it. TEST it when its done. The S7 can, (rarely) go bad. Like any part that moves and is touching another moving part. Maybe Ray has an extra laying around?)

When I measure the continuity, before starting, of the metal plate across the plunger measures correctly. While running I can see in the measurement that the circuit then opens. I'm guessing that the plunger under this metal "strap" is the culprit and it's right on the razors edge of some kind of problem. My next step is pull the Lockoutswitch (already removed front shroud) and visually inspect and see if there is something obvious. I need to review the TM, but i'm wondering if slightly "sanding" the plunger "nipple" would be sufficient? (Do not think so) It seems that whatever is wrong is ever so slight and that the humidity/temp is just enough to push it one way or the other.. (To properly test the S7, I would run 24 volts through it, (when removed) and have a Volt meter in sires. Then when it reads 24 volts, and I have wiggled the crap out of it, I would be sure its not a loose/broken/ mostly broken wire problem. Test, do not assume.)

Open to see comments

 

[chiefgguy]

Open to see comments

I was able to get some quality time with the generator this evening, with TM in hand!!! This will probably go sideways as I explain it, but hang in there!

This evening the generator was in it's "will not start" mood. so before doing a bunch of clunking around, I started doing quite a bit of measuring around the SLS (starter lockout switch). I was able to measure the pins in S8(?) and they were measuring "closed" then I measure around the switch lugs. This didn't measure closed.. Then I measure from the copper plate from the left to the right (taking the measurement on right at the lug) and this would measure OPEN.

Finally, just started pressing around on the copper 'bar' and low and behold it would start! Very puzzled.. Reread TM, and reread it again!

Took the two "screws" out to lift the copper housing unit off the SLS. inspected and measured. and used some extremely fine sand paper on the points. plug back in and try to start, no go.. Press the "point" together, it starts. Inspect further, hold up to light and I could see there's was a gap on part of the connection, which started to explain why "pressing" it would aid in the start. Read TM again! (I guess I was hoping for something new)

So, now turn adjustment nut to "make" the gap go away.. reconnect and it started! This is progress right here! NOW for the adjustment.. i wasn't convinced the plunger was working, but wasn't prepared to pull the whole switch apart, much more involved than I had time or daylight for. The reason I felt it wasn't "doing" anything is when i pushed on the "pin" it would just bottom out.. it wasn't spongy or otherwise have resistance of any sort. As i thought about it, if the generator is not running it should be in a position to be ready to start so there shouldn't be resistance, or so I think.

re-install the copper housing, check for start, and it starts.. but now I'm concerned the plunger is not working.. read TM AGAIN.. Follow the steps to do the adjustment to disconnect Switch (with gen running) and adjust "nut" to be .040 gap (using gap tool).. This time, i watch as the generator starts (YES) and then!!! The plunger pushes the copper bar out, so it must be working. shut down generator watch points close.. put tools away!

Now, we wait, since there seems to be some influence of the weather on what was happening, it will sit and we will periodically check for it to start. Although I'm feeling pretty good about it!

While i feel good, i'm not sure.. but hopefully adding some of this color will help others.. I can say if you are reading this and have similar problems.. be sure to search and read extensively all that you can find.. You eventually start to get a mental picture of what is supposed to be happening, and yes the TM is quite interesting.

I'll come back and post as I get a better idea if we've resolved this! Thanks @Guyfang and @Ray70 , for your continued input, wisdom and experience!

 

[Guyfang]

Now your cooking with gas!

As long as it starts. As long as you do not get starter run on, (starter clash to me) then you got it right. Its Miller time!

And its always better to know, then not know, (assume) when fooling with something new.