Kubota M108SHC starting issues, starts sometimes, sometimes not, hit or miss

[TxCuzzz]

All,

Never had a starting issue with this tractor. First cold day down here in South Texas, started right up, ran like a top.

Next day (saturday) would not start no matter what i did. Cranks fine, getting fuel under pressure out of the rail to the injectors.

Would not even crank over with a squirt of ether, so i am thinking it is some sort of electrical/glow plug issue.

Tried it yesterday morning, started right up like it always has. Ran about 10 minutes, shut it off once nice and warm, immediately tried to start again, would not start.

Tried a few minutes ago, still no start.

It has a glow plug relay (relay,heater 3N300-75213) which i have confirmed is the correct part.

My question is, what else should i check on the electrical system to see if there is something else simple that might be keeping it from starting?

Don't mind replacing the glow plug relay, but if something else is there that is easy to test/replace, i would like to know about it in advance.

Thanks in advance for your time and replies.

 

[Russell King]

Don’t use ether on Diesel engine or you can damage the engine

 

[TxCuzzz]

Don’t use ether on Diesel engine or you can damage the engine

Thanks for the reply Russell, but other than expressing an opinion, you did not really provide any useful info. If you read the post, you will see that i said i used it to test to see if i was getting any ignition/glow/etc.. You probably know that if there was ignition, then with ether, it would at least try to turn over.

For every person like you that says do not use ether or starting fluid, there is someone else who will say it does not hurt the engine. So i know all of that.

Hopefully someone will have some info on what else i can check other than the glow plug relay before i send it on to the shop.

Have a great day!

 

[Russell King]

Duplicate post deleted

 

[TxCuzzz]

Not really an opinion on modern design Diesel engines since the glow plug will ignite the ether but you can do whatever you wish to do.

I have no idea what problem your tractor has so didn’t make random suggestions for you to try

Thank you.

 

[Russell King]

Not really an opinion on modern design Diesel engines since the glow plug will ignite the ether but you can do whatever you wish to do.

I have no idea what problem your tractor has so didn’t make random suggestions for repair.

You have a super great day yourself and bless your heart.

 

[dvcochran]

All,

Never had a starting issue with this tractor. First cold day down here in South Texas, started right up, ran like a top.

Next day (saturday) would not start no matter what i did. Cranks fine, getting fuel under pressure out of the rail to the injectors.

Would not even crank over with a squirt of ether, so i am thinking it is some sort of electrical/glow plug issue.

Tried it yesterday morning, started right up like it always has. Ran about 10 minutes, shut it off once nice and warm, immediately tried to start again, would not start.

Tried a few minutes ago, still no start.

It has a glow plug relay (relay,heater 3N300-75213) which i have confirmed is the correct part.

My question is, what else should i check on the electrical system to see if there is something else simple that might be keeping it from starting?

Don't mind replacing the glow plug relay, but if something else is there that is easy to test/replace, i would like to know about it in advance.

Thanks in advance for your time and replies.

Did it hit on ether? Glow plugs help cold starts but don't really have anything to do with normal starting.
You are getting fuel TO the injectors?

Kubota Tractor M108SHC Parts, Kubota Tractor (kubotausa.com)

Look at the supply pump. There are electrical connections going to it. Maybe that is a starting point, something to do with the fuel solenoid maybe?

 

[JerryMT]

All,

Never had a starting issue with this tractor. First cold day down here in South Texas, started right up, ran like a top.

Next day (saturday) would not start no matter what i did. Cranks fine, getting fuel under pressure out of the rail to the injectors.

Would not even crank over with a squirt of ether, so i am thinking it is some sort of electrical/glow plug issue.

Tried it yesterday morning, started right up like it always has. Ran about 10 minutes, shut it off once nice and warm, immediately tried to start again, would not start.

Tried a few minutes ago, still no start.

It has a glow plug relay (relay,heater 3N300-75213) which i have confirmed is the correct part.

My question is, what else should i check on the electrical system to see if there is something else simple that might be keeping it from starting?

Don't mind replacing the glow plug relay, but if something else is there that is easy to test/replace, i would like to know about it in advance.

Thanks in advance for your time and replies.

Welcome to the forum.

I looked at the supplied part diagram and i don't see any glow plugs. The starting aid for your tractor is a heater grid in the intake manifold (See the parts diagram one of the people supplied.) You are lucky it probably isn't working because a shot of starting fluid might have ignited explosively in the intake manifold.

I would make sure that the intake manifold heater relay is supplying current to the heater grid when you try to start. I would suspect that either the relay is not working or the heater itself has failed. Make sure that when the starter is actuated that there is voltage to the relay.

By the way, check you operator's manual to see if starting fluid is recommended for cold starting of your tractor. Most modern tractors should not use starting fluid and most OEM 's don't recommend it.

 

[GreensvilleJay]

I was curious...so.......I looked at the linked parts diagrams...
I think # 371000 Inlet manifold, shows the 'glow plug', though not labelled, it's above #100. It should have a heavy duty wire going to it. Same setup as my forklift had.... It heats up small volume of air in the intake.
You NEED a really,really good battery to supply power to it AND crank over the engine !\

Easy to test.
.1st step.... put a DVM or trouble light onto the connection and ground. Turn key or press button for 'glow plug heat'. Meter should say 10-12 volts or the light will light up
.2nd step.... Turn key or press button for glow plug heat for say 15-20 seconds. Now CAREFULLY feel around the base of the heater CAREFUL !! It could be hot, REAL HOT. If it's NOT hot and you have 12 volts to it, it's burned out. If you remove the wire, and check with ohmmeter, an 'infinite' reading means it's open aka dead aka busted. A good one will read maybe 1/4 to 1 ohm.

There should be a fuse for it, maybe 20-30 amps ??

Without a wiring diagram , hard to say what the real values are.

hmm..how old is the diesel fuel ? Cold enough to 'gel' ??

 

[TxCuzzz]

I was curious...so.......I looked at the linked parts diagrams...
I think # 371000 Inlet manifold, shows the 'glow plug', though not labelled, it's above #100. It should have a heavy duty wire going to it. Same setup as my forklift had.... It heats up small volume of air in the intake.
You NEED a really,really good battery to supply power to it AND crank over the engine !\

Easy to test.
.1st step.... put a DVM or trouble light onto the connection and ground. Turn key or press button for 'glow plug heat'. Meter should say 10-12 volts or the light will light up
.2nd step.... Turn key or press button for glow plug heat for say 15-20 seconds. Now CAREFULLY feel around the base of the heater CAREFUL !! It could be hot, REAL HOT. If it's NOT hot and you have 12 volts to it, it's burned out. If you remove the wire, and check with ohmmeter, an 'infinite' reading means it's open aka dead aka busted. A good one will read maybe 1/4 to 1 ohm.

There should be a fuse for it, maybe 20-30 amps ??

Without a wiring diagram , hard to say what the real values are.

hmm..how old is the diesel fuel ? Cold enough to 'gel' ??

Welcome to the forum.

I looked at the supplied part diagram and i don't see any glow plugs. The starting aid for your tractor is a heater grid in the intake manifold (See the parts diagram one of the people supplied.) You are lucky it probably isn't working because a shot of starting fluid might have ignited explosively in the intake manifold.

I would make sure that the intake manifold heater relay is supplying current to the heater grid when you try to start. I would suspect that either the relay is not working or the heater itself has failed. Make sure that when the starter is actuated that there is voltage to the relay.

By the way, check you operator's manual to see if starting fluid is recommended for cold starting of your tractor. Most modern tractors should not use starting fluid and most OEM 's don't recommend it.

Thanks for this info. I went back and looked at the supplied drawing and i did find the heater you referred to. I also did not find any "glow plugs". I was under the impression it had glow plugs because one of the descriptions of the relay said something like "Relay Heater Glow".

Yesterday it started right up and used it for a couple of hours. Cut it off when i got home, waited a minute and it started right back up.

I should mention that the ambient temperature is now back up in the 60's and not near freezing.

Could not start or use it today, but will try tomorrow if we do not get the forecast rain.

I also noticed a thermo sensor located immediately above the heater, so perhaps it is not functioning properly and causing the engine to not start.

Regardless, you have all given me several more things to check if it decides not to start again.

Perhaps i will just have to wait for another cold spell to see how it acts.

Thanks again to you all!

 

[TxCuzzz]

I was curious...so.......I looked at the linked parts diagrams...
I think # 371000 Inlet manifold, shows the 'glow plug', though not labelled, it's above #100. It should have a heavy duty wire going to it. Same setup as my forklift had.... It heats up small volume of air in the intake.
You NEED a really,really good battery to supply power to it AND crank over the engine !\

Easy to test.
.1st step.... put a DVM or trouble light onto the connection and ground. Turn key or press button for 'glow plug heat'. Meter should say 10-12 volts or the light will light up
.2nd step.... Turn key or press button for glow plug heat for say 15-20 seconds. Now CAREFULLY feel around the base of the heater CAREFUL !! It could be hot, REAL HOT. If it's NOT hot and you have 12 volts to it, it's burned out. If you remove the wire, and check with ohmmeter, an 'infinite' reading means it's open aka dead aka busted. A good one will read maybe 1/4 to 1 ohm.

There should be a fuse for it, maybe 20-30 amps ??

Without a wiring diagram , hard to say what the real values are.

hmm..how old is the diesel fuel ? Cold enough to 'gel' ??

The item above 100 that you mention is a thermo sensor. Playing the Kubota Diagram hide and seek game, i found it numbered and identified on diagram 395000 engine electrical part. The heater the other person mentioned is #150 under the item 100 you mentioned.

That said, i will run the tests that you said if and when either it stops starting again, or i just have some time to do some testing.

Trouble is that once you get the tractor/shredder going, you need to be out on it trying to catch up.

Even when small items break, wear out, or do not work as they should, it seems no Kubota Dealer stocks parts anymore and they all have to order them in. Cannot remember the last time they actually had a part in stock ready to sell around here.

Going back to what you said above about a fuse, all i could find in reference to the heater, was the relay heater. I could not find a fuse marked for the heater/glow plug/etc..

The fuel is not old at all. Had new diesel delivered a month to 6 weeks ago, and changed all of the filters on the tanks and the filter, water seperater, etc., on the tractor itself.

IN reference to diesel gelling, i looked it up and found that diesel will gel at 15 degrees F. The temperature here was hovering right around that mark on the day it would not start, but it was also around there on Friday when i started it and it ran all day, and the following day it was well above that, but still would not start.

I think the next time it is going to be down in the teens, i will drap a cover over the hood to the ground and then put a heat lamp under it and see if that helps it to start.

Once again, thanks for all of the info and suggestions and we will see how things play out going forward.

I hope you all have a great New Years!