Kubota engine difficult to turn over when cold (not battery)

[Furu]

Now I am not an expert on diesel engines but I am constantly learning. This is another opportunity, I hope.

I have Cummins, Perkins, John Deere (when they still made their own) and a Kubota diesel engines. Question/issue is with the Kubota (49Hp).
The Cummins and the Perkins all have timed relays running the glow plugs. The John Deere and the Kubota are timed by the operator.

Now this issue has existed since I got the equipment back in 2014. Not something new. The OEM told me just use whatever GP time was needed to get it to turn over.
I have always thought the Kubota had a battery that was a bit undersized by the OEM but that is what they installed so that is what fits and is in use. The battery tests good and has a full charge when this happens. If I run the GP for the recommended 10 seconds cold weather, most of the time it barely turns over 1/2 to 1 turn then the starter chatters as if it does not have adequate battery power. If I then run the GP another 10 seconds it will normally crank and start. Occasionally it still barely turns over then chatters. After the third 10 seconds the engine turns over and starts fine. Yesterday this was repeated so that I eventually had 60 seconds on the GP. Yes I know that is a lot.
Other than burning out the GP what is the issue with excessive use?
Assuming it is not the battery and if it was why would it be fine after multiple attempts to turn over and multiple GP drains?
I know the heating from the GP warms the cylinder and makes the engine easier to start. Does the heating effect of the GP in any way change the resistance of the engine in the power required to turn it over? I almost now think that is what is going on. With 10 seconds the battery does not have the required CCA to turn it over but with the heated air somehow reduces the torque required to turn the engine over. Are the GP's possibly a problem? Just seems odd that the more time the GP are on the easier it is to crank the engine. I thought it made it easier to start not crank.

 

[Hall00]

Glow plugs do nothing for the crank, just help with the start.

Check your battery cables and grounds for clean and tight contact. How do you know the battery is good? Has it been load tested? An auto parts store will run that test for free.

Sounds to me like a connection or battery issue. Glow plugs pull a decent current and if the battery can't recover quick enough it can do what you describe.

 

[mini14]

Ever think the starter is weak

 

[RoyJackson]

I suggest adding a block heater...cold oil in the sump doesn't help starting

 

[seville009]

If you have a good battery jump box, or even a spare battery (that has higher cca than the one installed, and that is fully charged), hook either one of those up before your first attempt at starting.

my bet is that the battery is just not strong enough. OEM specs aren't necessarily the best; for batteries, I always look for one that has the highest CCA that will physically fit.

I have an ASV skidsteer with a Perkins diesel. I'm in the northeast and use it for snow removal. If it's really cold (below zero) and parked where I can't plug in the block heater, it will crank really slow and weak - not enough power to start. I just hookup my jump box (Noco GB150) and it will fire right up. Battery is fine in warmer temps; just needs an assist sometimes.

 

[Slowpoke Slim]

I suggest adding a block heater...cold oil in the sump doesn't help starting

This is more likely where the issue lies. The oil you are using.

First of all, how "cold" are we talking? I mean real numbers. What is your ambient air temperature when you say it's "cold"? None of that "wind chill" propaganda, tractors don't care about "wind chill".

If it's actually COLD where you are, switch to a synthetic oil. Else wise, look at the viscosity of your oil, and if you're sticking with Dino oil, swap out to a thinner weight "W" number.

I use synthetic oil here, along with an engine block heater, an oil pan heater, and a hydro sump "pan" heater. It regularly gets to -40F here in winter. I have no problems starting my tractor in dead of winter. Only takes one cycle of the glow plugs and it starts.

I did replace my worthless wet cell OEM battery with an AGM battery in it's first winter. The first time it hit -30F, the battery was stone dead. Never happened again once I put in the AGM.

 

[RjCorazza]

I know lead acid batteries get warm while charging. I assume (?) They also generate heat while under load also. Is it possible that the improvement in cranking after a few glow plug / starting cycles is heating up the battery? That is a curious pattern - it's usually downhill after the first starting attempt.

Regardless, it sure sounds like the battery is not up to snuff for the temps involved. A new, larger CCA battery, 0w-x or 5w-x oil, and block heater would help cold weather starting. It's always prudent to remove and clean battery cable connections, as well as the starter connections. (Start with the connections).

 

[dodge man]

I agree how cold is cold? If it’s 30 out, that’s not normal. If it’s 0 out, I’d say it’s somewhat normal. Load test the battery like already mentioned if you haven’t. I bought one a couple of years ago, less than $50.

 

[newbury]

Another reason Location matters.
°F or °C, the lower it is the thicker the oil AND it also degrades battery performance.

 

[5030]

Never an issue with either of my Kubota's I upgraded the starting batteries to the largest that would fit in the tray (in my case Group 31's) and the highest CCA ratings and I change out my starting batteries ever 3-4 years anyway. I consider a staring battery to be a consumable, just like lubricants and filters.

One of the most neglected parts on any tractor, next to the air filter element.

 

[nybirdman]

'On my Kubota I use a battery tender and a block heater if really cold(+10F).My glow plugs stay on for more than ten seconds and usually I give it at least two cycles if cold out.Mine now sits in and unheated barn but for ten years was out doors.

 

[5030]

In my situation, I have no power in the barn. They both have OEM block heaters that have never been plugged in.

 

[rScotty]

Never an issue with either of my Kubota's I upgraded the starting batteries to the largest that would fit in the tray (in my case Group 31's) and the highest CCA ratings and I change out my starting batteries ever 3-4 years anyway. I consider a staring battery to be a consumable, just like lubricants and filters.

One of the most neglected parts on any tractor, next to the air filter element.

Yep. That's what I do too. His problem sounds like battery or connectors. It took me way too long to realize that batteries are consumables, and that we can add cables, connectors, and hold downs if the battery is a wet cell type.

Just like any other other consumable, as soon as the factory battery shows the slightest weakness I replace it with and AGM type having a lot more CCA. My go to test is to check voltage an hour or two after charging and see if the battery retains that same reading after sitting a few days. Good ones won't drop 0.1 volts. Right now I'm running group 31s with 1125 CCA. It's hard to find good batteries these days. For years I used Optima round cells, but they are inconsistant the last few I've bought.
I researched batteries a lot this year since it was battery time for most of our fleet. Batteries tend to be priced and warranteed by how long they are expected to last. So a battery that only lasts half as long costs half as much. Or vice versa.

I hate swapping battery & battery parts, and like that AGM batteries do not eat up the battery cables and connections. My stock Kubota battery was a wet cell, and the fumes not only ate up the cable connection, the negative to ground copper cable itself was eaten up with corrosion inside of the insulation. That made for weird starting problems even with a good battery and connectors that were clean....the cables were shot! There was never any acid spilling out, so this was simply fumes...or maybe something that happened during manufacture.

BTW, as to glow plug timers....I thought that all Kubotas had glow plug timers. Ours is a the same 45 to 60 hp motor as the OPs, and is a 2008 model. It has a GP timer. About ten seconds, but can be repeated by cycling the key switch.

rScotty

 

[rScotty]

FURU, slow cranking can't be many things. If it isn't battery and cables, it can only be oil viscosity, block heaters, or a bad starter. BTW, oil viscosity includes both engine and trans/hydraulic oil. There's a story there, and it fooled me once.

Everything except the starter is easily tested, and in my over 50 years of mechanics I don't think I've run into more than one or two weak starters. One I remember needed brushes and the other had a field coil problem. Both were old. So probably not the starter.

If your Kubota wasn't starting, that can be lots of other things. But slow cranking only has a few possibilities.
rScotty

 

[nyone]

Ever think the starter is weak

This is a real thing. Starters do get weak.

My 09 accord would crank slow when cold. Replaced the 5yr old battery and still slow. Opened up the starter and found 2 of the 4 brushes broken.

 

[WranglerX]

If you are still using 2014 battery that came with tractor, that is most likely your problem.... IF you put a jump box on battery/tractor before first start and it fires right off, its a good indication you good battery is not so good...

 

[Furu]

It is not a Kubota tractor but a Kubota engine on another piece of equipment. A Sawmill to be exact.
1. The starter was replaced under warrantee several years back as it did develop a problem that I blamed on just this issue but was told by the supplier that it was in no way related. The problem deteriated so that eventually the starter made the chatter sound no matter what.
2. All the battery cables have been replaced. The battery has been load tested. It has happened with a battery charger hooked up after a full charge with the same result. Yes it seems odd that the issue goes away the more the GP are used thus having drained the battery more before start,
3. The oil is synthetic at the weight recommended for temp range.
4. My cold is not a real COLD but a mere 30 F but it has happened at 45 F as well.
5. What I have not done is hook up a spare battery in parallel to see if it happens (I don't have a spare battery and would have to borrow from some other engine.
6. The battery space is so tight that nothing bigger will fit or I would have done that years ago. I may have to fab a new location for the battery and go bigger but that is a problem that I wanted to avoid.
7. My theory was that the GP actually changed the air density in the cylinder making it easier to turn the engine over due to compressibility. Did not see how but wondered. Based upon all the comments that can't be a valid theory.
8. Starter could be undersized but why would Kubota have done that. It most likely is that the battery size just does not have enough power. Can't remember the battery spec CCA but the battery meets it. A spare jump box or battery would be a real pain to use all the time but may have to consider it.
9. No block heater on the engine and not always power available anyway.

 

[5030]

Whatever you do, DO NOT USE STARTING FLUID. It will destroy the motor internally.

 

[Doughknob]

I think....it is a loose electrical connection. Besides battery cables, there are other wires going to/from the starter solenoid and switch. I think your heating the glo plugs and crank attempts is shaking or heating up a loose connection. "check every connection."

 

[5030]

Yep. That's what I do too. His problem sounds like battery or connectors. It took me way too long to realize that batteries are consumables, and that we can add cables, connectors, and hold downs if the battery is a wet cell type.

Just like any other other consumable, as soon as the factory battery shows the slightest weakness I replace it with and AGM type having a lot more CCA. My go to test is to check voltage an hour or two after charging and see if the battery retains that same reading after sitting a few days. Good ones won't drop 0.1 volts. Right now I'm running group 31s with 1125 CCA. It's hard to find good batteries these days. For years I used Optima round cells, but they are inconsistant the last few I've bought.
I researched batteries a lot this year since it was battery time for most of our fleet. Batteries tend to be priced and warranteed by how long they are expected to last. So a battery that only lasts half as long costs half as much. Or vice versa.

I hate swapping battery & battery parts, and like that AGM batteries do not eat up the battery cables and connections. My stock Kubota battery was a wet cell, and the fumes not only ate up the cable connection, the negative to ground copper cable itself was eaten up with corrosion inside of the insulation. That made for weird starting problems even with a good battery and connectors that were clean....the cables were shot! There was never any acid spilling out, so this was simply fumes...or maybe something that happened during manufacture.

BTW, as to glow plug timers....I thought that all Kubotas had glow plug timers. Ours is a the same 45 to 60 hp motor as the OPs, and is a 2008 model. It has a GP timer. About ten seconds, but can be repeated by cycling the key switch.

rScotty

Optima's were good until Johnson Controls sub contracted most of them offshore. Then they went downhill rather quickly. Far as I know, the only ones still produced at the Waterville, Ohio plant are the blue top marine batteries. My farm is about 20 miles north of them.

I just buy my flooded cell jars from a volume dealer now, in my case the local Freightliner dealer I retired from. They go through batteries like water so they are all fresh. Been using the Delphi brand, not sure who makes them but I have excellent luck with them. Personally speaking, I think Optima's are over priced and poor quality (life) today.

Neither of my Kubota M9's have a timer on the glo plugs, I just do the second count in my head and never more than 10 seconds no matter how cold it is outside. If they aren't red hot in 10 seconds, you have other issues (like a weak battery) for instance.

Mine are a bit older than yours, 2002 and 2004.