glow plug indicator ?

50shootr

New member

Equipment
B6100D, Honda 70 fourtrax STIHL MS 250
Nov 4, 2012
28
0
0
So. Dartmouth,Ma.
Hi ..I recently bought a b6100d 910 hrs, it has a new glow plug indicator, new glow plugs, starts right up using glow plugs,but should that element showing thru the g p indicator hole light up? whats the purpose of the glow plug indicator? Thank You Ed
 

MagKarl

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L245DT
Aug 2, 2010
663
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0
Olympia, WA
Mine doesn't really glow brightly, it does warm up and you can tell it's hot after a minute or so though.

My manual says that when you can see that the indicator is hot, that your glow plugs have heated the combustion chambers enough that you can attempt to start the engine.
 

kubotasam

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Equipment
B2410, B7100dt, B7500,Woods BH750,Landpride 2660RFM, Tiller, B2781 Snowblower
Apr 26, 2010
1,205
128
63
Alfred Maine
I have never seen mine change color when I heat the glow plugs. I know it is working because my tractor starts good. It has been that way since I bought the tractor 7 or 8 years ago.
 

Lil Foot

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1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,577
2,636
113
Peoria, AZ
My B7100 indicator is not visible in bright sunshine, but glows a dull red in low light conditions. (after about ten seconds) A far more experienced tractor hand that I told me that the indicator coil, when new, is bright, shiny bare metal & glows brightly. As it ages, it oxidizes & gets covered with dirt, masking the glow.
 
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Stubbyie

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Jul 1, 2010
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Midcontinent
Search for a different post within the last week of this post---start looking about 08Nov12 forward. SDVic said that if glow plug indicator is NOT glowing it means the plugs are getting too much current flow and will soon burn out. Apparently the indicator acts as an inline resistor limiting current to plugs. Post lists several causes indicator may not be glowing.
 

kubotasam

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Equipment
B2410, B7100dt, B7500,Woods BH750,Landpride 2660RFM, Tiller, B2781 Snowblower
Apr 26, 2010
1,205
128
63
Alfred Maine
Search for a different post within the last week of this post---start looking about 08Nov12 forward. SDVic said that if glow plug indicator is NOT glowing it means the plugs are getting too much current flow and will soon burn out. Apparently the indicator acts as an inline resistor limiting current to plugs. Post lists several causes indicator may not be glowing.
It does act as a resistor to limit the voltage to the glow plugs while preheating them. What SD Vic said was that if you bypass the indicator/resistor you will soon burn out the glow plugs. Here is his post---


"The glow indicator is made by NGK and is stamped on the back side of it's housing with a particular ohm 'resistance' and is designed to work in conjunction with the appropriate NGK OE glow plugs that would be in your Kubotas engine.

The coil, while it does glow red and gives the operator an indication that current is flowing also regulates the amount of power the plugs get so they don't 'burn' up. If the coil is not 'glowing' red power may not be getting to the glow plug tips and bypassing it will cause the glows to fail very quickly."

----- He does state that it will glow "red". Like I said earlier, I have never seen mine glow red. I know all my glow plugs are working and I know the indicators are functioning properly as I have tested them all with a Ohm meter. I have 2 B7100's and both act the same. Perhaps if I went out in the dead of night and preheated the glow plugs I might detect some red. But during the daylight when I mostly run my tractors they do not glow red.

I would not want someone to think their indicator was defective on a tractor just because it did not glow bright red.
 

Lil Foot

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1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
7,577
2,636
113
Peoria, AZ
On a lighter note, a co-worker asked me where he could get a new cigarette lighter for his dad's tractor.... you guessed it, he was lighting his cigs with the glow plug indicator. Not sure if he was pulling my leg, I'll have to try & light something with mine one day.
 

WingNut

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Equipment
L2850 Kubota c/w Loader
Feb 29, 2012
50
0
6
Northern Ontario
I own a L2850 4x4, and I have never been able to see even a dull red colour out of my glow plug indicator, however I also know that the glow plugs are working. I'll have to try it at night sometime, just to see if there is even the faintest of noticable colour.
 

Dennis

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Jul 28, 2010
79
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Queensland Australia
A B7100 that never glowed, that I can see , in over 15 years. I usually have to pre heat for about 20 to 30 seconds (in a mild climate ). Does that sound about right ?
 

G-Man

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Equipment
B7500, ZD221
Jul 27, 2012
81
0
6
Excelsior, AR
On my B7500 all I have is indicator lamp that when the ignition switch is in the glow plug position it only tells me there is 12V going to the glow plugs. Since my tractor has the manual version (me) I put the ignition switch there and hold it long enough to warm up depending on the outside are temp. Since the tractor has it's own heated and air'ed bedroom it doesn't take very long.
 

Dennis

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Jul 28, 2010
79
1
0
Queensland Australia
I have 4 different manuals for my B7100 , one of which is the "Kubota Technical Manual B5100 ,B6100 , B7100 ". Does anyone else also have this manual ?

In the Glowplug section it states (in very broken english) that if one glow plug fails then the other plugs and the indicator will continue to operate , but with decreased electrical current so that heating up of the indicator will be weakened;
accordingly check all the glow plugs and plug cords.

Also says that maximum amperage at glow plug is achieved after 30 secs.

Anyway for the moment I have a more immediate priority of replacing the front axle pivot pin bushes.
 

B9200Kubo

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Kubota B9200
Aug 20, 2022
7
0
1
Shipman, Virginia
If the glow plug indicator is burnt out, do the glow plugs work ok?
I see my Kubota B9200 wiring diagram confuses me. It appears the two are connected in series.
 

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kubotasam

Well-known member

Equipment
B2410, B7100dt, B7500,Woods BH750,Landpride 2660RFM, Tiller, B2781 Snowblower
Apr 26, 2010
1,205
128
63
Alfred Maine
If the glow plug indicator is burnt out, do the glow plugs work ok?
I see my Kubota B9200 wiring diagram confuses me. It appears the two are connected in series.
If a B9200 is wired like a B7100 (I would assume it is), then yes they are wired in series and if the indicator burns out the glow plugs will not work when the key is turned to the pre heat position. They will work when the key is turned to the start position as this key position bypasses the indicator/resistor. I can't tell much from your picture so once again I am assuming your B9200 is wired like a B7100,
 

Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
5,239
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Williamstown Ontario Canada
Go to kubotabooks.com and download a B7100 WSM. It is high quality and makes understanding the two operating modes of the GP's easier.
How did you decide the glow indicator is faulty?
If the GP's are burned out then the glow indicator will not glow.
The key switch provides two alternative paths for power to the GP's.
Path 1 Pre-heat is thru the glow indicator whose job is to lower the voltage and current seen by the GP's a little.
Path 2, key in start, power flows from the key switch directly to the GP's. This is because the current draw of the starter is lowering the voltage seen by the GP's.
Dave
 

Russell King

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L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
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Austin, Texas
In Dave_eng’s description you may have to replace “key switch” with just “switch” if you have an older tractor since the key switch is often just an on off switch and there is a separate switch to activate the glow plugs and the starter.
 

B9200Kubo

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Kubota B9200
Aug 20, 2022
7
0
1
Shipman, Virginia
If a B9200 is wired like a B7100 (I would assume it is), then yes they are wired in series and if the indicator burns out the glow plugs will not work when the key is turned to the pre heat position. They will work when the key is turned to the start position as this key position bypasses the indicator/resistor. I can't tell much from your picture so once again I am assuming your B9200 is wired like a B7100,
Thank you, Kubotasam.
The wiring diagram of B9200 shows:
1. When the key is turned to counterclockwise to preheat, the indicator is lit thru pin #19, and the reduced voltage heats up the plugs. But, if the indicator is damaged, the plugs have no voltage to heat up.
2. But, the key is turned to" start", 12 volt power directly via pin #17 is applied to the heating plugs.