Kioti CS2510 Dies/won't keep running/rough starts

MowinLife · Apr 3, 2020

Hi friends,

I have a Kioti CS2510 which was running fine several times after our mild winter. A few days ago I started up and it ran like usual for ~5 minutes until the RPMs dropped, the engine shook and died. Since then I haven't been able to keep the engine running for more than a minute.

Here's my symptoms:

Get on the tractor, heat engine, startup. Engine cranks, then runs but rough. Sometimes it'll run smooth for 3-5 seconds and then rev to 2-3k before coming down to idle speed again, then RPMs drop and engine dies. Other times engine never makes it up to idle speed and then dies within 5 seconds of starting. Either way, while running RPMs fluctuate pretty wildly.
From tailpipe, small white cloudy puffs while cranking. Then a big black puff when engine takes. Then exhaust is clean while engine "runs" and dies.

Here's what I've tried already:

Drained and replaced fuel.
Checked fuel line, replaced old fuel filter.
Fuses don't look blown at a glance.
Checked air filter, looking good.

This is my first time working on a diesel engine, but hopefully some guidance on where to troubleshoot next will help me out. The strangest thing to me is that it failed while running.

All help is greatly appreciated!

And yes, I'm in neutral

JimR · Apr 3, 2020

I'm not familiar with your machine. It sure sounds like a fuel starvation problem. Do you have an electric fuel pump? If so, take the fuel line off at the injection pump and insert it into a bottle. Turn on the key to make sure there is fuel coming out. If that is good then I would try bleeding the injectors by loosening the injector lines and cranking the motor over until you see fuel spitting out of them. My neighbor has to have me do this to his JD at least once a year due to running his machine out of diesel. I realize that you didn't run your tractor out of fuel but maybe it has air in there from draining it all out and changing the fuel filter.

MowinLife · Apr 4, 2020

Thanks, Jim. It does in fact have an electric pump, so today we checked the fuel line like you said. Fuel comes out at about two drips per second when I'm bleeding (we have an autobleed system), and about as fast when I'm cranking. Is that an appropriate level of flow or should we be expecting a much higher rate?

TnAndy · Apr 4, 2020

I'd agree....sounds a lot like fuel starvation.

Does your machine have a clear (plastic or glass) filter bowl for the primary fuel screen ? My previous tractor had it on the side, current Yanmar has it under the right rear fender where the small electric booster pump is also located.

In this photo, the plastic fuel bowl is barely visible about 1 o'clock at the top of the frame:

Start the tractor and look at the fuel bowl.....does it STAY full of fuel ? If not, you have a tank obstruction. Pull the line off of the bottom of the tank and if you don't get HOSED with fuel, you definitely have something in the tank blocking fuel flow. Happened twice to me on my Yanmar, and happened on a Mitsubishi dozer I had.

JimR · Apr 4, 2020

MowinLife said:
Thanks, Jim. It does in fact have an electric pump, so today we checked the fuel line like you said. Fuel comes out at about two drips per second when I'm bleeding (we have an autobleed system), and about as fast when I'm cranking. Is that an appropriate level of flow or should we be expecting a much higher rate?

My NX4510 squirts a stream. I believe that these pumps have a 4 - 5 psi range. Your smaller tractor may be less. Two drops a second is not enough to run anything. I would take an air line and back flush the line with air pressure. Maybe you have something in it or a very plugged up filter. There could also be something in your tank plugging the pickup tube. If you put air to it. Make sure you remove the gas cap, Have someone listen to the air in the tank while you or somebody else flushes the line backwards.

TnAndy · Apr 4, 2020

JimR said:
There could also be something in your tank plugging the pickup tube. If you put air to it. Make sure you remove the gas cap, Have someone listen to the air in the tank while you or somebody else flushes the line backwards.

If you put air to it, and it is something in the tank, you'll simply blow in aside, and the problem will return.

Just PULL THE LINE OFF the bottom of the tank.....you should get plenty of flow. Try the easy, simple check first. If you don't, something is in the tank blocking flow. IF that turns out to be the case, I'll give you more on how I got it out without removing the tank.

If you get plenty of flow out of the tank outlet, then try air in the rest of the lines/etc.

MowinLife · Apr 4, 2020

Seems like you all have suspicions that the line or tank may be clogged... when I changed the fuel filter, the fuel on the tank side was draining at what seemed to me to be a fast rate, probably took about 10 minutes to drain the 5gal reservoir. Am I right to assume that nothing's blocking the tank? Assuming there's nothing wrong there, should I be checking the pump next?

JimR · Apr 4, 2020

MowinLife said:
Seems like you all have suspicions that the line or tank may be clogged... when I changed the fuel filter, the fuel on the tank side was draining at what seemed to me to be a fast rate, probably took about 10 minutes to drain the 5gal reservoir. Am I right to assume that nothing's blocking the tank? Assuming there's nothing wrong there, should I be checking the pump next?

Sounds like the fuel line is clear before the filter. Sounds like a bad pump. You could check this by filling a small plastic bottle with fuel and running a fuel line into it and to the pump If you get the same results then I would change out the pump. You are sure the filter/filter housing isn't blocked or partially plugged up. Is the filter before or after the pump?

MowinLife · Apr 4, 2020

The pump is after the filter.

So I kept messing around with the fuel delivery and discovered that I had unobstructed flow up to the pump, but only a drip after. Got in and took out the pump and tested it on another circuit, and sure enough it makes a pumping noise but no fuel flows through. Took it apart and everything mechanical looks good, so I'm assuming the electrical component has failed. Going to the dealer soon to get a replacement; hopefully that's the fix. I'll post an update afterward.

Thanks everyone for your help so far. I've learned quite a bit about diesels and my tractor along the way