Engine sputtering...What's going on?

[escavader]

Drained it twice, or thrice! I can hear the fuel pump and I have added something similar to Power Service. No improvement.

sorry i just reread the post you did say that.
Did you check to see if the air filter canister was plugged,or filter.Try to see how high rpm works without the filter mabey.
ALAN

 

[Lockport]

It'll idle at any speed. Even WOT. It only starts sputtering if you driving or working an implement stationary. While driving one might compare it to something in the fuel tank getting caught in the flow and plugging the outlet. Since it will idle so that seems to rule out a floating blockage as a hard fact.

The air filter is new this spring.

 

[Volfandt]

Well, we're about to run out of the easy fixes. Theres a few more to try before we get serious......

It still sounds like either a fuel delivery problem and/or perhaps an intake air problem.

New filters, check.
New clamps, check.
New fuel, check.
Fuel conditioner, check.

Lets see, she runs fine at idle and only starts to stall either under load or when rpm is increased.
At this point I still discount mechanical.

Fuel flow appears to be good to the pump as you've indicated you've gotten drenched by fuel but,,,,, a partial restriction could allow enough fuel to start and idle but not enough to run under load and/or at high rpm.
One thing to try is to disconnect the fuel line just before the 1st filter and w/an air compressor, blow back towards the tank. Make sure the fuel cap is off and you're set at no more than say 70 psi. Don't need to compress the fuel in the tank.
Put the line back, do the self bleed and try it. If it runs better for a longer amount of time, an obstruction in the tank amy be the culprit.

One other easy fix would be to make sure its not the air filter and/or it's assembly. Run it stationary without the filter in it long enough to see if the problem clears.

Try those and let us know.

edit:
I see you've posted whilst I was and you've answered my two thoughts.
So you say it'll run good at any speed as long as theres no load, right?
Drive it or work an implement and it tries to stall, right?
I dunno, I'd still try it without the air filter and if that fails blow back towards the tank.

If it were a switch, it should try to cut out as opposed to stuttering.

 

[crazyal]

A co-worker has the same problem. He went through everything you've tried with no luck. One thing he said is you can see foamy fuel inside a bowl. His is a m5040. The dealer finally looked at it and said they thought it was the secondary pump but when they went to work on it they said they found hay inside the fuel line. However it still does it. He was told there's no strainer in the bottom of the fuel tank. I'll let you know more when he does.

Here's an interesting side note. My Case backhoe had a hard starting problem. When cold it started like normal, 30 seconds or so, was cold out. When warm it would take even longer but once started it would run fine. I had just replaced all the filters but did it again with no luck. Case BHs have a filter and water separator that screw on like a oil filter and a small inline filter with hose clamps. I didn't bother to change the small filter but just blew it out/ inspected it. Turns out after lots frustration that there was small hole in the in-line filter. I think someone on a baord like this told me about a problem they had so I removed it and pressurized it. It was too small to leak fuel but would suck in air. Anyway been there, done that, it's no fun.

Maybe the next time you drain the fuel you can pull the fuel lines to see if there's a small hole somewhere.

 

[NY_Yankees_Fan]

I had similar problems as you are having. Is the fuel pump running when u turn the key on? I had a stick hit the rubber boot on the shaft for the fan, it came loose and took out the wire to the fuel pump. Turn the key on and make sure u can hear the pump running.

 

[Lockport]

I had similar problems as you are having. Is the fuel pump running when u turn the key on? I had a stick hit the rubber boot on the shaft for the fan, it came loose and took out the wire to the fuel pump. Turn the key on and make sure u can hear the pump running.

Interesting note. I can hear the fuel pump, but in hindsight, it may actually be emitting intermittent sounds. At first it is a constant clicking, but after a few moments it seems to be interjected with pauses of no more than a second. Is that normal?

I am going away this morning for 10 days so won't be able to do anything until then. I may try a new pump, depending on replies.

CRAZYAL: Thanks, that is also another possibility that I will certainly look at.

 

[Soundguy]

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

Interesting note. I can hear the fuel pump, but in hindsight, it may actually be emitting intermittent sounds. At first it is a constant clicking, but after a few moments it seems to be interjected with pauses of no more than a second. Is that normal?

I am going away this morning for 10 days so won't be able to do anything until then. I may try a new pump, depending on replies.

CRAZYAL: Thanks, that is also another possibility that I will certainly look at.

 

[GA WTDeer]

Interesting note. I can hear the fuel pump, but in hindsight, it may actually be emitting intermittent sounds. At first it is a constant clicking, but after a few moments it seems to be interjected with pauses of no more than a second. Is that normal?

I am going away this morning for 10 days so won't be able to do anything until then. I may try a new pump, depending on replies.

CRAZYAL: Thanks, that is also another possibility that I will certainly look at.

My buddy has a Koiti ck25 that let the hydro filter go to long. He was having the same problems, It was just when a load was on causing the engine to bog, and run like ____ Just another thought maybe you have some blockage. Try it seems you tried everything else CLay

 

[chucko]

you try to blow the fuel line out with air?

 

[Lockport]

you try to blow the fuel line out with air?

No. I don't have a compressor. May buy one though.

Anyway I went to a dealer. Spoke to Zee Sherman Mekanik and he zaid take zee line off the filter by the engine and turn the key and see if its getting a good supply of fuel. (All of a sudden he was cured) Which it is.

I tried to blow back through the line but these filters are one way and, other than turning beat red, that yielded no results.

I put it back together and started it and as it idled it sputtered once and then stopped (sputtering). I took it out in the yard and drove around in circles at about 1900 RPM and it seemed fine. I started to think maybe something blew out just when it started again.

It is definatly not air restricition because I have a restrictor gauge on the air filter housing and if I take the battery/rad screen cover off and cover the inlet the air restrictor gauge starts to close drastically and it is otherwise wide open.

I don't have time now, but I only turned on the pump downstream side of the downstream filter, and may go back in and try from the upstream side in case there is something in the hose. Should repeat with gravity flow at the filter upstream of the pump. I got a bath yesterday so I know between the tank and that rearward filter is clear, but again this is an intermittent problem so I wouldn't rule out somethng in the tank. Also, I should remember that this started before I changed the filters.

I think there is something in the tank that is semi submerged and is periodically floating in front of the outlet.

My buddy has a Koiti ck25 that let the hydro filter go to long. He was having the same problems, It was just when a load was on causing the engine to bog, and run like ____ Just another thought maybe you have some blockage.

My hydo fluid is really clean and I think it if was a dirty hydro filter it would have a consitency to it. Interesting though.


It's gotta be fuel delivery.

 

[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.