L3400 Loses Power

[Weekend_Warrior]

Hello everyone. I've been lurking around a bit for some time..

Decided to get some work done this weekend and everything was good until my L3400 started losing power under a load...

I managed to get it to run at a low rpm and get it back to where I can work on it....

It will run all day just sitting there at a low rpm... when I increase the throttle it will die...

I have replaced the fuel filter, drained the tank and replaced it with good diesel, and bled all of the lines up to the injectors...

Interesting point also: The air bleeder valve has to be left open about 2-3 turns or it will die straight away...

I did run the fuel tank pretty low before refueling.... so, the 2 things I'm looking at tomorrow morning are:
1) Check the fuel tank to make sure there isn't something in the bottom preventing good fuel flow..
2) Replace the fuel line from the tank to the filter in the event that it is collapsing (had a 4x4 chevy do this to me in high school- chased it about a week)

I would very much appreciate any opinions of other things I might need to check...

With the bleeder valve closed it won't start.... I will probably start with a complete purge of the fuel lines again tomorrow 1st thing just to make sure I've got this done correctly....

Thanks in advance!

 

[Weekend_Warrior]

Update:

I just went through everything again...

1) Remove cap from fuel tank, check hoses, and remove vent hose to ensure good air flow.
2) Confirm engine only runs with air bleeder valve 2-3 turns open- Still bogs down when I apply more throttle.
3) Re-Bleed injector pump and CLOSE air bleeder valve.
4) Re-Bleed Injectors- 2-3 sets of cranking 10-12 seconds each..

Engine is trying to start now, but won't run... It comes up to just enough RPM to kick the starter out and then dies...

I am confident that the injector lines are bled now... It didn't do this before with the bleeder valve closed...

I think the hoses are okay because I have good flow from the tank to the filter. Before I changed the fuel filter, the fuel in the sight glass was dropping below the filter... I thought for sure this was going to be the issue

On the way into the house to check this thread I had a thought:

I'm going to check the air filters, etc... as this is my sister in law's L3400 Kubota (sorry- for search engines to help others with L3400 Problems like this) I don't know the maintenance history (if any)....

Could just be a dirty air filter now.... Here's hoping

 

[Weekend_Warrior]

Re: L3400 Loses Power- Problem Solved!

Okay.... I finally got it!

I started with the basics:

1) Are we getting fuel from the tank to the filter?
Answer: Very Little
Solution: Removed the fuel line from the filter and bumped it with compressed air.... cleared it right up. (There are dangers involved with compressed air & fuel/oil- Don't do this unless you understand them)

2) Drained the tank (5gal) in about 3 minutes... MUCH better than a dribble.

3) Still had the same problem.... Sludge was restricting the flow through the fuel filter. Removed the filter and blew out the assembly.

4) Attached hose directly from tank to injector pump to test for about 10 sec.... Works Awesome!

5) Re-assemble clean fuel filter, and make sure inlet and outlet are clean...

WORKS FANTASTIC!

This machine probably hasn't run this good in months. Just about all they do with it is move hay bales....

I'm glad this forum was here. Hopefully this will help others with their L3400 Kubota won't start problems!!!

Now..... I'm going to go finish discing my food plot

 

[Eric McCarthy]

Re: L3400 Loses Power- Problem Solved!

Well gald we could help!

 

[KubotaTech]

It was running when the bleeder was open because it was using the fuel that was coming in that little line to run at a low speed. Glad you figured it out.

 

[Bulldog]

Sounds like some fuel conditioner would be a good idea if it sets alot. It probably had algea in the tank.