L4240 White Smoke and Stumbling Idle on Cold Start

[Member]

Hi,

Recently my L4240 started producing about a half minute of white smoke with a stumbling idle on a cold start. See below for a video.

This has happened consistently on the last four or five starts. I turn the key and the glow plug relay makes a nice snap. I wait until the glow plug light goes out before cranking it over. It always starts on the first try. The outside temperature has ranged from 8 to 32 degrees Fahrenheit. The tractor is about a year old and has 50 hours on it. It is always parked inside an unheated building. I have owned it since new. I fill it with diesel from yellow 5 gallon cans. The fuel I'm using has been in there for several months. I don't use any diesel additive.

This is new behavior and something it has never done until the last four or five starts. Any ideas?

Thanks,

--
Dan

 

[Little Red Tractor]

Best first guess is bad/contaminated/moisture fuel. First thing would be to try some fuel conditioner. Might be a worth it to change your fuel filter. Always try the simple things first.

 

[avc8130]

My L45 sounds and acts like that when it is cold also. I did some searching on the web because my L39 never sounded like that. It seems to be that the 4cyl Kubota's are just like that in the cold from what I have found. Rumor was that Kubota adjusted injector timing for max power while still meeting the emissions and it is a bit too aggressive for cold smooth starts.

ac

 

[TripleR]

Looks just like my L5740 when cold. It makes more noise and puts out more smoke than my old L5030.

 

[lew61]

I have a new (less than 20 hours) L4240 and it's been starting fine in our winter temps (8-32 degrees). From past experience, I'd suggest taking Little Red Tractor's advice. White exhaust means water to me.

 

[kuboman]

If this just started then I would suspect the glow plugs are not up to snuff. Although my 5740 does that at 50*. If it is new for your machine then something has changed. Either the GP"s or fuel.

 

[crashz]

I suspect the fuel. Try a conditioner and check the water / fuel separator.

 

[nybirdman]

Yes,summer fuel and no additives.Add Powerservice or Howes.I use Powerservice year-round in my fuel for my L4240,always starts fine.I do have a block heater I use when real cold.

 

[art]

Try some power service it is what we use!

 

[Chilly807]

Try some fresh fuel as soon as you get the chance. If the fuel is several months old it will be summer fuel without the winter additive package. Adding an additive directly to the tank probably isn't a good idea as it's hard to mix it properly in the tank. It acts like it's missing on a cylinder or two until the heat builds up in the cylinders.
It may just be the nature of the beast, although you did say this is new behaviour. If it's just old/summer fuel it won't hurt much, other than running rough until it warms up a little. It works ok once the engine warms up? If you're getting some snow, it shouldn't take long to get rid of the tankful of fuel in it now.

Sean