Engine sputtering...What's going on?

[Lockport]

My Nh did that.. and it was because it wasn't getting a steady flow of fuel from the tank.. IE.. when it was sucking air.. it made no sounds.. and as it got sips of fuel is made sounds... Check to make sure that lift pump is getting a good fuel supply.

keep posting back.. we will get to the end of this!

Soundguy

All the lines look to be in good condition. No chaffing or damage anywhere I can see that air may be sucking in. I haven't, however, removed the skidplate and, although the lines are wraped in loom it is possible there is more to that story.

Unfortunately, I do have to go away this evening so this saga will have to continue next week on the same channel, but thank you, everyone.

 

[Soundguy]

Hmmm.. i wonder if it is sucking air? ( at a fuel line )

soundguy

 

[spectre520]

I am real interested in the outcome of this thread as my BX23 with 180 hrs on it is doing the same thing. I too have serviced it and replaced the fuel filters. (both)

I checked fuel pump flow (gee, that sure seems like an abundant fuel flow) And, just generally doing I think everything that has been outlined here. I have noticed that my problem surfaces when I am under load and mowing using my 60" Walco 3pt finish mower.

It actually runs out fine for awhile but as the tractor reaches optimal operating tempurature, it starts to falter under load. If I kick the pto out for a moment it seems to clear it's throat and come back to life. Although, I do notice that the engine doesn't seem to run as smoothly as it did before it started acting up.

 

[Lockport]

Hmmm.. i wonder if it is sucking air? ( at a fuel line )

soundguy

I am still out of town and cannot try anything, but it occurred to me that the maintenance schedule recommends replacing the fuel lines after, I think, two years. Perhaps there are micro cracks or fissures in the line that are allowing it to do just that.

 

[Soundguy]

Wow! kubota is on a real money making roll.. replacable fuel lines and hyd hoses at frequent intervals.

man.. I think all the other tractor manufacturers are missing out. heck. they should make every part of the tractor replaceable every few hundred hours here and there.. that would really drive the profit margin way up!!

dang... and to think i have some tractors with OEM fuel lines on them after 50-60 years!! and even a few modern ones with 'soft' lines that are nearing a decade!!

I gotta hand it to kubota.. they really know how to keep their hand in the pocket of thier tractor owners!!

Soundguy

 

[Tommy V]

When I was a motorcycle tech we ran into problems you described. As fuel is used form the tank air must enter to replace the volume of fuel used. If air cannot get into the tank a vacuum can form. Even a slight vacuum can lead to fuel starvation problems. Try running with the cap loose in the situations where the problem occurs. Just make sure the fuel is kept in the tank, it can stain plastic and sometimes remove paint. If that is the problem replace the cap with the check valve or breather in it.

 

[Lockport]

When I was a motorcycle tech we ran into problems you described. As fuel is used form the tank air must enter to replace the volume of fuel used. If air cannot get into the tank a vacuum can form. Even a slight vacuum can lead to fuel starvation problems. Try running with the cap loose in the situations where the problem occurs. Just make sure the fuel is kept in the tank, it can stain plastic and sometimes remove paint. If that is the problem replace the cap with the check valve or breather in it.

Everybody hear that! Why hasn't this been suggested yet? Seriously. I will be home this weekend and this is the first thing I am checking and it won't surprise me in the slightest if that is exactly the problem!.

 

[Soundguy]

If that is the issue, and it is drawing enough vacume to starve the lift pump/ injector pump.. then when you opened the tank to add the dewaterer, or remove the fuel filter.. you should have heard a whoosh and/ or gurgling.. etc... should have been very obvious.

Soundguy

 

[Harry c]

.. you should have heard a whoosh and/ or gurgling.. etc... should have been very obvious.

Soundguy

Not necessarily. Sometimes the rubber fuel line can get sucked shut if there is just a small amount of vacuum. Happens most often where the line makes a bend.

 

[Tommy V]

It is very easy to miss the slight hissing sound when the cap is removed, especially if you are not looking, or specifically listening, for it. It doesn't take much of a vacuum to overcome gravity which is the way fuel gets to the pump.