MEP-003A

[Johncar48]

Good day to all.
My generator runs great sometimes and other times hard to start and blows a lot of smoke. Let it sit for an hour or so and it fires right up and sounds great.
I try to run it at least once a month. Just installed a new starter and batteries. Also th percent gauge bounces all over the gauge. Sprayed selector switch very well and worked it back and forth...did not help.
Suggestions would be greatly appreciated.

John
Kerrville, TX

 

[Scoobyshep]

Good day to all.
My generator runs great sometimes and other times hard to start and blows a lot of smoke. Let it sit for an hour or so and it fires right up and sounds great.
I try to run it at least once a month. Just installed a new starter and batteries. Also th percent gauge bounces all over the gauge. Sprayed selector switch very well and worked it back and forth...did not help.
Suggestions would be greatly appreciated.

John
Kerrville, TX

So its hard to start when hot? What color smoke?

Sprayed the selector switch with what? assuming gauge selector.

 

[Johncar48]

Sprayed with CRC Contact Cleaner.
Smoke is blueish gray.

 

[Guyfang]

A gauge that bounces back and forth often is caused by a wire loose in the gauge.

Starting problem, I would look at the heaters and glow plugs. Test/inspect IAW the TM.

Have you downloaded the TM's. Maybe even read them a bit?

 

[Johncar48]

Have the TM and have read some parts but not about the issue.

 

[Guyfang]

The preheat relay, K2 is automatically turned on, when you start the set. If the heaters are bad, you can get problems like you have.

 

[Johncar48]

Even in summertime weather in Texas, do you need to use the preheat function?

 

[Scoobyshep]

Even in summertime weather in Texas, do you need to use the preheat function?

Depends on how hot the block is, and what your compression is like.

when is it harder to start, when its been off for awhile, or after its been running, stop it and restart it?

 

[Johncar48]

copy

 

[Guyfang]

The heaters are a part of the start function. You have no control over it. Unless you unhook them. Scoby is correct. If the heaters are in order, then a compression check would be a good idea.

 

[Johncar48]

The preheat relay, K2 is automatically turned on, when you start the set. If the heaters are bad, you can get problems like you have.

heaters are all good but, I'm only getting 21v to the heaters with 24v going into K2. will this cause the heaters not to get hot enough.

 

[Scoobyshep]

heaters are all good but, I'm only getting 21v to the heaters with 24v going into K2. will this cause the heaters not to get hot enough.

how are you taking these measurements? voltage at K2 when heaters are off and voltage at heaters when K2 is on? Might be normal voltage drop from loading. My personal opinion on testing glowplugs is to remove them power them and observe how long it takes them to heat and how they look when heated.

 

[Johncar48]

how are you taking these measurements? voltage at K2 when heaters are off and voltage at heaters when K2 is on? Might be normal voltage drop from loading. My personal opinion on testing glowplugs is to remove them power them and observe how long it takes them to heat and how they look when heated.

takes about 22 seconds for them to get glowing red hot

 

[Scoobyshep]

takes about 22 seconds for them to get glowing red hot

that sounds about right

 

[Johncar48]

takes about 22 seconds for them to get glowing red hot

But that was with the heaters removed and connected directly to the batteries. So I know they were getting 24V

 

[Scoobyshep]

when i get a chance i can see what my 003 reads . where exactly did you meter it?

 

[Guyfang]

when i get a chance i can see what my 003 reads . where exactly did you meter it?

I think a 3 +- drop in voltage is about right. Cant remember, and there is nothing in the TM.

 

[Scoobyshep]

But that was with the heaters removed and connected directly to the batteries. So I know they were getting 24V

24.8 battery voltage 22.5 volt on cyl 4 glowplug

 

[Ray70]

When you checked the voltage, where did you pull your DC- from? You need to test from the block to the plugs. I once had a similar issue where I had 24V when probing from the glow plugs to the main terminal block ground screws inside the control panel, but upon closer inspection I only had about 4V between the glow plugs and the engine block. The problem turned out to be that the ground strap going across the engine mount closest to the batteries was rotted away. replacing the ground strap fixed everything.
I can not explain why that strap is so important, one would expect the ground running through the body of the starter motor would be enough, but there is obviously something else going on that makes that ground strap very important to the glow plug circuit.

 

[Scoobyshep]

That ground strap is also very important because its the chassis ground for the ac output.

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