Problems Kubota L3608

Cybersonic

New member

Equipment
Kubota L3608
Oct 25, 2024
4
1
3
Thailand
My Kubota starts perfectly.
The engine runs smoothly when idling, exhaust fumes are OK.
The hydraulics work both at the front and the rear.

When I accelerate, it works fine for about 6-10 seconds, then you can hear the engine starting to slow down, it starts to misfire and the speed drops significantly.
At this point, it also starts to smoke and stutter.
It no longer responds to the accelerator - so pressing the throttle to full has no effect.
Reminds me a bit of a "banana in the exhaust", i.e. a blocked exhaust.
Let the engine idle, wait a moment and I can rev it up again to 2,000 rpm, for example, which it holds for 6-10 seconds.
Then the whole thing starts again.

What could it be?
What could I check?

Today I bled it several times - that improved the symptoms a little, so that it at least holds the 2,000 for the 6-10 seconds mentioned, but it didn't get rid of it.
The exhaust pipes are clear from the engine through the manifold to the end (I had initially suspected a bird's nest in the exhaust).
The air filter is clean and clear.
The tank is full.
The diesel filter is new.
The fuel tap (with filter) is new (water separator?)

History of the tractor:
I got it from a dealer who buys used tractors, dismantles them and rebuilds them.
Completely repainted and replaces consumables.
It is possible that it had been standing there for a long time.

I had the tractor delivered - the tank was of course pretty empty.
So I filled it up. Then I drove the tractor (about 3 kilometers) and used the mulcher to mulch an area of grass of about 1,000 square meters. That worked great.
Then the tractor stood still for 4 days.
Today the problems mentioned occurred, after about 200 meters of driving.
 

D2Cat

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Lifetime Member

Equipment
L305DT, B7100HST, TG1860, TG1860D, L4240
Mar 27, 2014
13,811
5,545
113
40 miles south of Kansas City
Perhaps there is something blocking the fuel from flowing. Start checking flow out the tank then proceed to filter and to the IP.
 
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Russell King

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Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
5,356
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Austin, Texas
IP = Injection Pump
 
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Cybersonic

New member

Equipment
Kubota L3608
Oct 25, 2024
4
1
3
Thailand
Perhaps there is something blocking the fuel from flowing. Start checking flow out the tank then proceed to filter and to the IP.
Problem solved!

I removed all the hoses from the tank to the next element and reconnected them to check whether there was a blockage anywhere.
I couldn't see any blockage in any of the hoses, but I suspect that the blockage was there and was washed away by the diesel flow.
After I had finished that, I started the engine, bled the system using the vent screw and the engine hummed like a kitten, even at higher revs and continuously.
Worked in the field yesterday and the machine ran perfectly.

This morning on the way to the field the same problem again - but it quickly turned out that it was a porous old fuel hose that had lost fuel and was probably also taking in air.
I replaced this, bled the system and the tractor is running again.
I have ordered new fuel hoses.
After delivery I will replace all the fuel hoses, it will get a new air filter and I will probably also change the cooling hoses soon.
 
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D2Cat

Well-known member
Lifetime Member

Equipment
L305DT, B7100HST, TG1860, TG1860D, L4240
Mar 27, 2014
13,811
5,545
113
40 miles south of Kansas City
Problem solved!

I removed all the hoses from the tank to the next element and reconnected them to check whether there was a blockage anywhere.
I couldn't see any blockage in any of the hoses, but I suspect that the blockage was there and was washed away by the diesel flow.
After I had finished that, I started the engine, bled the system using the vent screw and the engine hummed like a kitten, even at higher revs and continuously.
Worked in the field yesterday and the machine ran perfectly.

This morning on the way to the field the same problem again - but it quickly turned out that it was a porous old fuel hose that had lost fuel and was probably also taking in air.
I replaced this, bled the system and the tractor is running again.
I have ordered new fuel hoses.
After delivery I will replace all the fuel hoses, it will get a new air filter and I will probably also change the cooling hoses soon.
Any problem with your tractor is an opportunity to learn more about it, how it works and why it may not work sometimes. Good for you!!
 
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