Cold weather starting on L4630GST

[Llaves]

I'm having a hard time starting the tractor on cold mornings (overnight low sub-zero, teens to twenties when starting the tractor). The glow plug light comes on, but on for 5-10 seconds. The engine turns over strong (the battery is good), but doesn't catch - just belches black exhaust. Typically takes 2-3 cycles of this to start. I've tried multiple cycles of turning the key to trigger the glow plug timer, but the light stays on only a few seconds on the second or third try. On my Gehl skidsteer with a Kubota engine the recommended glow plug time was 30-45 seconds at these temperatures - much longer than the tractor is timing.

What should I try next?

I've read numerous references on the forum to a decompression valve, but can't find anything about it in the operator manual. Does an L4630 have a decompression valve?

 

[Dave_eng]

I once asked a mechanic at a Kubota dealership how they got all the tractors in their yard started in very cold weather. He explained a trick they use to get the glow plugs to cycle independent of the timer. He uses this trick to cycle the glow plugs a second or even a thrid time if the tractor does not fire up immediately.
Here is what he said:
put your shuttle lever in forward position and hold the key switch like you would start the tractor. Due to a safety switch the tractor will not start but the glow plugs will come on and then just put your lever back to neutral and start your tractor

My tractor is a M7040 and even though I have a plugged in block heater I use this trick to cycle the glow plugs as it makes the engine start much smoother. I count to 10 and then start the engine. Their is no indication that the glow plugs are warming up but the difference when I start the engine is very noticeable. With the block heater operating, the glow plug timer sense the warm engine and does not turn on the glow plugs at all

I think the same or similar tricks will work on all newer Kubotas. You might just have to ask the dealer's mechanic if yours is different such as having a HST.

Dave M7040

 

[Llaves]

Gave your method a try today. Overnight low was zero, about 25° when I went to start the tractor. The glow plug light came on for about 10 seconds at most. I put the shuttle in forward, and turned the key to the starter position (which of course didn't turn over the tractor). Put the shuttle back in neutral, stomped on the clutch and turned the key. Engine caught after about 10 seconds of cranking. This seemed better than the last time I tried to start it, when it didn't catch on the first two attempts. We'll see how this holds up over the rest of the winter.

Thanks for the tip.

 

[Bulldog]

It's funny how some have so much trouble starting in cold weather. Just to see if it would I started my L3000 one time at -11 with no glow plugs. It doesn't have a automatic controller so I no for sure it didn't have any heat to help out. My M9000 has never failed to start either although it doesn't get used much during the winter.

 

[Llaves]

I wouldn't have thought Georgia ever got that cold

I wonder if elevation might be part of my problem. From what I've read, elevation does impact non-turbo-charged diesel performance. I'm at 7500'. The tractor was bought from someone at 3700'.

 

[Bulldog]

Normally not that bad but every now and then we get some cold wind from the north. That winter I thought we were going to freeze to death.