Glow Plugs - How Long Do You Keep Them "ON" Before Cranking The Engine ?

[nbryan]

Thanks for that tip, I am currently away from the majority of my tools. I just remembered I have a test light in a trailer. I can at least test for 12V at each plug for power. I did locate and pull the relay off, it had some light oxidation, dirt etc. I reinstalled and kept my hand on it when in pre-heat mode and it did click. I kist didnt try that before removing. It was warmer today and only cycled plugs for about 10 sec. It turned over about 5 sec and fired up with some black/grey smoke but ran fine. Tomorrow I will test for voltage but dont have access to a multi meter currently. I am the 3rd owner, the last guy kept it outside under an awning for a few years and plugged in during winter so I am sure the glow plugs were put to task regularly.

Check with the power tester. If power shows with key at glow and dash indicating, then if that power is being used by the plugs to heat, the battery voltage will drop significantly compared to key just turned to on. If your tester is at all sensitive to a voltage drop, it may dim a little compared to how bright it is without the glow plugs drawing power.
1. Check for voltage at plug with key turned to glow.
2. If #1 shows voltage, move the tester to the battery and see if it dims at all when the key turns to glow.

5 seconds crank to fire sounds like no glow happening, given my experience with our same machine. No start with more than one full second cranking on mine is hard to remember happening ever, even when very cold temperatures well below freezing and cold cranking without any glow plug applied (accidentally). It fires and coughs and spews some exhaust soot for a few seconds, but it starts! Plugged in for a few hours and 5 seconds glow and it starts instantly, little exhaust soot.

 

[NCL4701]

My L4400 must not have that feature. Although I must admit I rarely use the GP as the temps here are usually above 60. On the rare 'cold' day I usually hold them on for about 5-10 seconds.

However, after reading some of the posts I may start using them regularly for a couple of seconds.

EDIT: Just went and looked back at my manual and it says don't use them unless below 23*F.

Thanks for pointing out the 23 degree thing. I’ve been in the habit of waiting for the glow plug light to go out before cranking. If the engine is already hot sometimes that’s about 1 second but I’ve always waited. Although I’ve read the owner manual cover to cover at least a couple of times, looking back at it mine says the same. Apparently I should quit wearing out the glow plugs.

 

[SidecarFlip]

I agree. With my B7100, if the engine is hot, no glow necessary. If it's a little cool or the engine has been shut down a while, (like over lunch) I glow at least 5 or 6 clicks. If it is a really cold, first start up, I glow 15 to 17 clicks.
I also use the decomp knob momentarily to let it spin up when it's cold. The old boy usually starts on the first crank, regardless of temp.

My M's both have the red knob, but I've never used it that I can remember. Not even sure it works actually. I'll have to try it tomorrow as I need to fire up the cab tractor to load some seed corn and it's cold and snowing here.

 

[Henro]

Found this in a Kubota manual.

 

[armylifer]

Found this in a Kubota manual.

View attachment 52391

This chart must be for those tractors that have an automatic glow timer. Still, it could be useful as a reference to how long one should hold the glow for those that do not have an automatic timer.

 

[Bmyers]

This chart must be for those tractors that have an automatic glow timer. Still, it could be useful as a reference to how long one should hold the glow for those that do not have an automatic timer.

I checked my manual, it states to turn on key, wait tell glow plug simple goes off, start tractor.

 

[armylifer]

I checked my manual, it states to turn on key, wait tell glow plug simple goes off, start tractor.

Yeah, then yours is an automatic timer. Mine is manual. You turn the key to the 1/2 position and look at the glow plug light on the dash to be sure it is on and you count a few seconds and then turn the key all the way over to the start position. I never tried it but I bet if I held the key in glow position the light would just stay on until I released the key. I think the glow plugs would ether burn out or just stop glowing without any way for me to know it at he time. I think all of my vintage BX's are the same.

 

[armylifer]

I checked my manual, it states to turn on key, wait tell glow plug simple goes off, start tractor.

Here is what is in the manual for the BX1870, BX2370, and BX 2670. I don't have a pdf of the operator manual for my BX1860 but the procedure is the same.

Turn the key to "PREHEAT" position
and hold it for about 2 to 3 seconds.
For the appropriate preheating time, refer to the table
below
Preheating Time
2 to 3 sec
5 sec.
10sec
Temperature
Over O'C (32‘F)
-5 lo O’C (23 lo 32'F)
4510 -5’C (5 to 23'F)
NOTE :
* Glow plug indicator (2)comes on while engine is being
preheated

 

[Bmyers]

Here is what is in the manual for the BX1870, BX2370, and BX 2670. I don't have a pdf of the operator manual for my BX1860 but the procedure is the same.

Turn the key to "PREHEAT" position
and hold it for about 2 to 3 seconds.
For the appropriate preheating time, refer to the table
below
Preheating Time
2 to 3 sec
5 sec.
10sec
Temperature
Over O'C (32‘F)
-5 lo O’C (23 lo 32'F)
4510 -5’C (5 to 23'F)
NOTE :
* Glow plug indicator (2)comes on while engine is being
preheated

My manual, they made starting my tractor simple for my simple mind.

 

[kubotafreak]

View attachment 52400
My manual, they made starting my tractor simple for my simple mind.

I own a l3560 and have never seen my glow plug display illuminate. Even with snow on the ground the display never illuminated. I have found it odd, however the tractor always starts right up. Went to a dealer this weekend and started a new machine, the glow plug symbol came on. Temp was probably 40 go figure...

 

[Henro]

This chart must be for those tractors that have an automatic glow timer. Still, it could be useful as a reference to how long one should hold the glow for those that do not have an automatic timer.

Maybe so, but it makes no difference really, whether a timer does it or a human does it, the recommended time would be the same in either case.

 

[daves31]

Yeah, then yours is an automatic timer. Mine is manual. You turn the key to the 1/2 position and look at the glow plug light on the dash to be sure it is on and you count a few seconds and then turn the key all the way over to the start position. I never tried it but I bet if I held the key in glow position the light would just stay on until I released the key. I think the glow plugs would ether burn out or just stop glowing without any way for me to know it at he time. I think all of my vintage BX's are the same.

Yeah before I found the chart in my manual I thought I was supposed to hold it till it went off. I held it about 20 seconds and it never went off. Only did that once. Now i just do 3-5 secs.