Tractor revs on cold start

[L4300DT]

i have a 2000 L4300DT and I notice when it's cold out and I first start it, it revs way up to 3000 or so before settling down to where I have the hand throttle set to....roughly 1500. If it's much below freezing I do glow plugs for 30 seconds or so. Just the idea of revving a cold diesel up past 3000 makes me squeemish, but is that normal? Perhaps I'm not glow plugging long enough and a bunch of unburnt fuel is being sprayed in there before it catches?

Also, a friend of mine, on cold starts, will run the glow plugs on his Kubota (old tractor, way before electronic control) even after it's started till help it smooth out a bit. Thoughts on this would be appreciated.

B

 

[85Hokie]

i have a 2000 L4300DT and I notice when it's cold out and I first start it, it revs way up to 3000 or so before settling down to where I have the hand throttle set to....roughly 1500. If it's much below freezing I do glow plugs for 30 seconds or so. Just the idea of revving a cold diesel up past 3000 makes me squeemish, but is that normal? Perhaps I'm not glow plugging long enough and a bunch of unburnt fuel is being sprayed in there before it catches?

Also, a friend of mine, on cold starts, will run the glow plugs on his Kubota (old tractor, way before electronic control) even after it's started till help it smooth out a bit. Thoughts on this would be appreciated.

B

Something must be "sticking" on the injector pump??? If you are NOT opening the throttle - how can too much fuel get there? Someone will tell you where to look - sounds to be that something is sticking WOT throttle then when the vibrations or heat or something kicks in .......it is released and runs back into idle.

If/when warm - does the throttle work as it should?

 

[L4300DT]

Absolutely, if it's cold out BUT the tractor has already warmed up, or not cold at all, it just fires up without the big rev.

When I say "revs", it just shoots up and straight down again. It doesn't stay up there there.

 

[North Idaho Wolfman]

What weight of oil are you running in it and when was it changed last?
Does it blow black smoke when it starts?
Does it blow any smoke when it starts?
What temp are you calling cold?

 

[L4300DT]

Hi Wolfman, I can't remember off the top of my head, but it's Kubota oil for all season use. I know they don't make it, but I did tell them I don't put enough hours on it to change it out as the season changes. I understand that will often mean it's not the perfect oil for any season. Tractor has 570hrs. Oild changed 80 hrs ago.

I'm in southern Ontario, and I'm not sure at exactly what temperature this starts to happen, but it certainly happens at -15 to -20 celcius so that would be 0 to -5 Fahrenheit.

When it's cold, it will certainly blow black smoke when it starts and stay smokey for a minute before going clear. If it's LESS cold, it might blow white smoke for a bit. If it's not cold at all, it just sends out a small puff of black smoke and goes clear right away.

I'm reading different thoughts on how long to run the glow plugs (mine's fully manual) with some folks sayin 60-90 seconds. Manual says lots less. Any harm in running them longer?

thanks very much!!

Brent

 

[Tooljunkie]

The L4610 i used to run would give a good snort when cold started. Same thing, will immediately idle down.

 

[North Idaho Wolfman]

I'm thinking, try treating your fuel, Stanadyne would be my #1 pic.

It might just be a flow problem.
Add some to the tank, don't really worry about getting it exactly right, even 3 or 4 times as much on the treatment won't hurt it.
Might also consider a biocide treatment like Soltron (weird name great product), just to make sure all the crud is out of the entire system.

 

[L4300DT]

Thanks wolfman, I'll give those a try. Can't hurt I suppose!

Appreciate the help,

B