L3400HST Loosing Power

[11bravo]

Kubota with 220 hrs has started to periodically loose power when mowing.
First time it did it I was thinking that somehow air must have gotten into the system. This is my first Diesel operated engine to own, so I don't much about them. I have replaced the fuel filter in the past, have read the manual on how to remove air. It has run at least a full season without any problems since that first fuel filter change. But now it has started loosing power. I went and bought a couple fuel filters with new o'rings and installed a new filter again.. and did the remove air thing again. There is plenty of fuel coming from the tank to the filter bowl when filter bowl is removed.

However, I did notice some stuff on top of the old filter that looked like algae fiber.

So after replacing filter and bleeding air it ran about 30 minutes and started loosing power again. I'm sort of at a lose as to what to look for now.
Are there any trouble shooting steps to follow for a problem such as mine?

 

[olthumpa]

. . . However, I did notice some stuff on top of the old filter that looked like algae fiber. . . .

Algae will grow in diesel if let to set in a tank. This could be from sitting around your place or from where you bought it. Only buy your fuel where they have a high fuel turn over.

1) Get some NEW FRESH diesel
2) Drain your fuel tank and lines - flush the tank if possible
3) Put on another new filter
4) Fill tank with NEW FRESH diesel
5) Bleed the lines
6) You should be good to go

 

[Tx Jim]

I see no need to drain the high dollar diesel out unless it's bio-diesel. Dino diesel doesn't go bad it just gets contaminated with water or dirt. Yes algae can grow in water contaminated fuel but can be killed with correct fuel additive.If you're getting air in the fuel filter then you need to determine how it's accessing the filter. Is tank vent open and not plugged by debris?

 

[11bravo]

Thank you for the replies.
Tank Vent, Where is it located?

Do you think I ought to loosen the nuts on the injectors to bleed air too. I read about that on the Orange Tractor site.
I'm pretty much a do it yourselfer, but haven't had any experience with diesels. But I'm getting some now.


I am going to go out to the shop to investigate it some more.

 

[cerlawson]

I have a small BX and it had all those same problems from new. Went through all sorts of changes. New filters, new tank cap (if plugged), changed fuel, etc. Finally I changed the fuel pump, even though it ran on the old one. Seems to have fixed it. Most of the trouble was with a partial full tank. Fill it and no sweat until half full.

The position of the tank is such that gravity helps to fuel it. Interesting that when changing fuel pump, I first just disconnected the power to the pump. As long as there was a half tank of fuel, it ran fine. Even on old filters. Gosh remindes me of the old Model

Only 150 hours.

The new pump was a different part number, due to replaced item. Hmmmm??

Gosh, it reminds me of the old model A Ford I had. No need for a fuel pump.

 

[helomech]

How is your air filter?

 

[11bravo]

The air filter looks ok, I slapped it on the shop floor to shake loose dust from it, but hardly any fell off.
I think I changed it last summer when changed the fuel filter also.

I figured out where the tank vent is and made sure it is clean. It wasn't plugged. Fuel filter still looks good. so I didn't change it out. I topped off the tank to top of neck, opened vent valve and started engine and watched air bubbles escape from the fuel. I let it run much longer than before when I bled the air. Owners manual says let the engine run 30 seconds then close the valve. So I let it run a couple of minutes while opening and closing the needle valve a couple of times and was satisfied no more air was in the lines.

Next I'll do some mowing and get back on the forum for a update. Hopefully a good one.

 

[11bravo]

I didn't get to mow but only for a 1/2 hr today. Tractor ran fine during that time.

But I wanted to say also is that I have noticed since I have been having this problem, that it always happens when the fuel gets below the vent line in the tank. So I'll continue to use the tractor till the fuel gets down to the vent or below and we'll see what happens this time. Then I'll report back.

 

[Bulldog]

Have you put any fuel conditioner in the tank yet. Since you thought it had algea it might be a good idea. In any case it won't hurt anything.

 

[11bravo]

Have you put any fuel conditioner in the tank yet. Since you thought it had algea it might be a good idea. In any case it won't hurt anything.

I haven't put any fuel conditioner in the tank. I think I mistook the stuff I thought was algae as small pieces of paper. And the reason I say that now, when I topped the tank after changing the filter, I use a red shop rag and a funnel to filter the diesel pouring from the container. That was a few weeks ago. The rag and funnel were still together in the place that I left them. Yesterday when I topped the tank off again from the same container I used the same rag and funnel. That is when I noticed a couple of small pieces of brown paper on the rag. The rag was still sitting on the funnel from the last use.

Since I last posted I have run the engine 1 1/2 hrs with a problem yet. I didn't check the fuel level this afternoon when I shut it down. I'll do that tomorrow before starting it up.