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.