X748 stalling problem

[RedHawkRidge]

My X748 is a 2012 model, with 350 hrs. Had no problems for 2 yrs of mowing (bought it used from the local JD dealer). This summer the unit stalled while mowing a hillside. When trying to restart, it coughed, sputtered, and fired on a couple cylinders, while throwing out heavy blue smoke. Got it to the dealer service dept. They ran it several times over a week's time without being able to recreate the problem.
So I got it back, and mowed for a few hrs until it stalled again. Got it on level ground and tried restarting again. It turned over several times and chugged to a start, again with lots of blue smoke billowing out. After 15-20 seconds, all cylinders were firing and the heavy smoke stopped. So I continued to mow without it quitting again. I can't see taking it back to the shop, when they can't see the problem.,
Is this JD model X series prone to this kind of problem? Does the fuel system or the crankcase oil work on a gravity type feed, which would cut off the engine if the unit gets on a steep grade? I really like this unit, but it's a problem that I worry will eventually cost me big bucks. Anybody with a diesel X signature model experiencing similar issues?
thanks
jim

 

[beenthere]

Suspect fuel related.. not knowing the history of the fuel supply nor what Deere checked out.. no immediate ideas to help. Doubt it is an X series problem.. the Yanmar's have a long solid history.

 

[Kish318420]

Do you use any diesel additives for preventing algae growth or water condensation in the fuel tank, lines, pump, injectors?

Could fuel pickup and line in tank have issues.

 

[Dave M7040]

Your fuel tank is under the seat correct?

Are there any hoses coming from the engine cylinder heads into the air filter assembly?
A crankcase vent system to burn any vapors from the crankcase.

The blue smoke you mention, which appears in the restarts, makes me think crankcase oil is finding its way into the engine's intake.

Is the engine turbocharged? It does not appear so.

I don't know how steep the slopes are where the machine stalls out.

Who changed to engine oil last? Was it filled to the mark on the dipstick or filled with the quantity of oil the spec's indicate the engine requires.

Too much oil especially on a slope where the oil is concentrated in one end of the crankcase may be leading to frothing of the crankcase oil producing a lot of fumes which then get back into the intake.

The engine up to and including the 2011 model had 2.6 liters in the crankcase. After 2011, the quantity increased to 3.2 liters. Tthe 3.2 liter would be your engine.

Take the air filter assembly apart like you were going to install a new filter element. Look for a small hose, perhaps 1/2" entering into the air filter housing from somewhere on the upper part of the engine.

If you find such a hose disconnect it and let it blow out into the open air while you test it again on the slopes, Tie a rag over it to prevent any dirt getting in.

The engine is designed to operate anywhere between the two lines on the dipstick. Drain the oil into a clean container and then pour it back in measuring how much you put in and bring its level to the lower mark on the dipstick.

Try cutting the slopes and see if the stalling and blue smoke restarts continue.

If they do not then we can talk about possible solutions.

After thinking more about your problem, is it possible the seat switch is the trouble when operating on slopes?

Dave M7040

 

[Spanner]

Were you low on fuel when you were mowing on the hillside and it stalled the first time?

In the X5-700's the fuel tank is shallow, flat and wide. The fuel pick-up has s large-ish 'sock', as a filter, on the bottom which somewhat resembles a pancake but is about the diameter of a coke can. (Hope you can visualise that?)

Because the tank is so shallow the pick-up & sock sit in a shallow recess in the floor of the tank - Which is under the seat base.

That helps the pick-up stay in the fuel pool. Unfortunately, it also provides a place for all the dirt (etc.) to gravitate towards and thus get sucked onto the filter sock.

You can imagine the rest...

To access this pick-up filter sock you must remove the seat, its runners and the fender-deck. Disconnect tail-lights and the little hook clip beneath the LH handgrip. (#3 in the parts pic. You have the tank on the right.)

The various hoses & wiring loom are obvious. Remove the pick-up & filter assembly carefully (It also contains the Fuel Gauge Sender Unit) and view inside with a torch.

Report what you find.

Tip out the fuel into a bucket or tray.

The filter sock can be cleaned with 'solvent'. It is not available seperately so you have to clean it. It is the circular shape above the gasket ring here:



:wrench:

 

[jenkinsph]

Were you low on fuel when you were mowing on the hillside and it stalled the first time?

In the X5-700's the fuel tank is shallow, flat and wide. The fuel pick-up has s large-ish 'sock', as a filter, on the bottom which somewhat resembles a pancake but is about the diameter of a coke can. (Hope you can visualise that?)

Because the tank is so shallow the pick-up & sock sit in a shallow recess in the floor of the tank - Which is under the seat base.

That helps the pick-up stay in the fuel pool. Unfortunately, it also provides a place for all the dirt (etc.) to gravitate towards and thus get sucked onto the filter sock.

You can imagine the rest...

To access this pick-up filter sock you must remove the seat, its runners and the fender-deck. Disconnect tail-lights and the little hook clip beneath the LH handgrip. (#3 in the parts pic. You have the tank on the right.)
View attachment 515021
The various hoses & wiring loom are obvious. Remove the pick-up & filter assembly carefully (It also contains the Fuel Gauge Sender Unit) and view inside with a torch.

Report what you find.

Tip out the fuel into a bucket or tray.

The filter sock can be cleaned with 'solvent'. It is not available seperately so you have to clean it. It is the circular shape above the gasket ring here:

View attachment 515023

:wrench:

Good post on tank cleaning and maintenance above.^^^

In the US a torch is called a flash light. If this were a gas tank instead of a diesel tank there may not be much left to report on.

 

[ccsial]

How long were you on the hillside before it stopped? I mow a steep ditch with my 748 but I'm only on it for a few minutes. My guess is it is not picking up fuel on the incline. Something has changed. Look for the simple things first.

 

[Todd NE WY]

I had this exact same problem with my x465. I thought it was the fuel filter, I changed it without improvement. I noticed when I changed it the hose was dry and cracked. Sure enough I replaced the cracked hose with a new piece and no more problems.

 

[Spanner]

I had this exact same problem with my x465. I thought it was the fuel filter, I changed it without improvement. I noticed when I changed it the hose was dry and cracked. Sure enough I replaced the cracked hose with a new piece and no more problems.

I suspect a 'similar' problem with stalling but not 'slope-related' like the OP has. Cracked fuel hoses will leak irregardless of the angle they are operating in my experience.

Which fuel filter did you replace Todd? There are two for your petrol engine. The one in the tank or the in-line one up by the engine?

Interestingly one tends not to see cracked fuel hoses on diesel machines. Quite common on petrol engines however.

Furthermore, the fungal growth seen in diesel tanks does not occur in petrol tanks.

Regards,
:wrench:

 

[Todd NE WY]

This was the filter near the engine and it is a gas motor. Looking back it probably wasn't running great anytime just more noticeable and finally died on the hillside.