John Deere Z930A

[Nwatson99]

Hello I just joined and wanted to seek advice from the professionals with a issue I am having.

I have a 2010 Z930a with 60" 7 Iron deck, hours are 282.2 to be exact.
Engine is 29hp Kawasaki
I mow roughly 4 acres per week sometimes twice in a weeks time.

Two weeks ago I was mowing like normal and all of the sudden spit, spat, sputter, like something was taking power from the engine big time.
I said heck okay no big time maybe a plug went bad, turned off the deck came back to the garage allowed it to cool for about 30 minutes, changed both plugs and while I was at it I inspected the air filter.
Then took off again and finished mowing

Next mowing about half way through, spit, spat, sputter, etc alright what the heck is going on here, so took it back to the garage and figured okay the fuel pump might be bad, so changed he fuel pump, fuel filter, disconnected all fuel lines looked through them, etc.

Third mow out, same crap it is like half way through the mow something just takes the life out of the engine.
Now there are no codes displaying, there are no trouble lights coming on, there is nothing happening other than what I have described to help me trouble shoot this thing and point me into the direction I need on what might be the source of the problem.

I service my machine faithfully, actually much better than the owners manual
Clean under the deck at least once per month
Change oil every 50 hours not 100 per the book
Grease the 5 zerks once per month
Every time I mow I blow machine off with a leaf blower
I only run unleaded plus or premium in my stuff period.

John Deere customer support is useless, they can only say these words: Take to the nearest dealership, here let me look them up and get you a phone number.

I would greatly appreciate if anyone has went through this and can help me out on what needs to be tried next.

 

[BBO]

I only run unleaded plus or premium in my stuff period. John Deere customer support is useless.

The first thing you need to do is slow down.:laughing:

Does the mower run ok until it gets hot, or does temp have anything to do with it starting back.
You say it sputters but never quits?
You need to determine if the problem is related to the PTO in any way. So when it starts the sputtering cut the blades off to see if this has any effect.

You can unscrew the gas cap when it starts the sputtering to see if the vent is bad. But don't leave this loose.

It might be a stopped up fuel filter.
Or it could be electrical related with a coil going bad.
What did the old plugs look like? Both the same?

 

[Nwatson99]

The first thing you need to do is slow down.:laughing:

Brother for 11K to mow my yard only and everything happening right after the warranty runs out is very questionable. :confused3:
Edit to add: This is the second issue that has happened to me this year, in May the drive tension idler pulley came flying out from underneath the mower, the bearing was perfectly fine, the pulley itself was made from inferior material and wore out the center of the pulley to twice the size it should have been.
John Deere has had complaints about this since the new pulley was a much stronger design, the material was thicker all the way around it, structural dows had been spot welded around the bearing hole for structural integrity, but John Deere even after having a JD service manager write a report and contacting them telling them the pulley was no good still would not replace it under warranty. Machine was little over 2 .5 years old with 249 hours on it when that pulley came flying out, so JDCS excuse was you did not take the machine to the JD dealer so we are not going to hep you out, but I took all the parts and components for them to take the parts off.
I asked the woman would you have paid for the roll back to come and get the mower and take to the dealership?

Does the mower run ok until it gets hot, or does temp have anything to do with it starting back.
You say it sputters but never quits?

I am beginning to think it is the heat, but the mower being air cooled there is nothing I can do to correct this, the blades are clean, there are no warning lights of overheating, no error codes, so I am scratching my head.

You need to determine if the problem is related to the PTO in any way. So when it starts the sputtering cut the blades off to see if this has any effect.

Disengagement of the deck helps some, but it will continue to spit and sputter when I try to drive it to the garage.

You can unscrew the gas cap when it starts the sputtering to see if the vent is bad. But don't leave this loose.

Zero effect

It might be a stopped up fuel filter.

Brand new filter and pump

Or it could be electrical related with a coil going bad.

I will call today and get one, is there any sensors that could be causing this?

What did the old plugs look like? Both the same?

Old plugs looked fairly new, quite shocked really on how clean they were.

Also I have performed the transmission service on both transmissions as well, but the problem was happening before performing the service, both transmissions have new filters and new fluid in them.

 

[BBO]

I am beginning to think it is the heat, but the mower being air cooled there is nothing I can do to correct this.

Ha. Man you want to work fast. :cool2:
1st let me say I am not familiar with your exact mower, I am just trying to help you sort this out.
Don't worry about the heat the air cooled is supposed to handle it. Something else is amiss...

If you suspect the coils or plus wires do this BEFORE ordering parts.
When the sputtering is present and it's "hot" as you suspect shut it off and pull a plug wire off.
Crank it back for just a short time to see what it sounds like running on one cylinder.
If it's way worse, put this one back on and pull the other one off.
This might indicate that it's not firing on one identified cylinder.
A mower will run on one plug but you can SURE tell it when it's missing; especially with the PTO pulling horsepower.
If this test is totally different to your observation of the "sputtering" then the problem may be elsewhere.

Normally if one side is not firing that plug will look way different so I am not sure a coil or coil wire is the problem. (you say both look good)
But the plug would need to be missing for a time to foul the plug up real bad.
You still have no idea if this is electrical or a fuel issue.
Heat will do funny thing related to the coils firing.
With a technical manual which I do not have for you mower, you can check the coils with a meter.
You could test the two coils with the wires off ground to all points and connectors/connectors to see if both test basically the same with no manual.
This might give you an indication. Inspect the plug wires carefully to be sure one has not came apart inside.

BTW "ethanol free" fuel is more important that high octane fuel.
At this point I am guessing you have a carburetor problem, but that is just a wild guess.

With it running put a voltmeter on the battery. What does it read?

 

[Nwatson99]

BBO
Thank you very much for your help, input, and diagnosis. I spoke with two more Kawasaki engine mechanics and one being a former JD service tech today on the phone
I explained to them the problem which I could explain to them a little better than to you and they both said exactly said the same thing as you did right off the bat, one of the coils is breaking down and overheating thus causing the engine to misfire.

I have both coils ordered which will be in my hands on Sat, so just as soon as I get them replaced and mow I will let everyone know if this was the issue.


The first time the mower did this, it felt and sounded like I had a plug go bad so that is the reason why I replaced them immediately after it cooled down, I did inspect the plugs and checked the gap which one was just a tiny bit larger than the other, maybe .001 to .002" difference, the gap guage could slide through with no friction so it was barely nothing. The plugs also looked clean, no carbon build up, they were just a darker color from the heat and firing. The coil wires which not much is visible looked perfect, no nicks, tears, and when it snapped on the plug it was nice and tight.

 

[mowerman05]

I have the same mower, same year just a few less hours and have had no problems so far. knock on wood. wish I could give some advice but have no answers to your questions. Good luck

 

[Nwatson99]

I have the same mower, same year just a few less hours and have had no problems so far. knock on wood. wish I could give some advice but have no answers to your questions. Good luck

Thank ya sir
It was the same with me, the first two years just clean the machine itself, under the deck, change oil, inspect air filter and grease, then right after the warranty goes out here came the issues.
I am still mad as a bull over the drive idler pulley flying out from under the mower and I will recommend you replace yours before you have issues with it and also have to replace the drive belt along with it "when my drive idler pulley came off of my mower it tore my belt up pretty good", like I said structural wise there is not much of a comparison from the old to the new they know or knew there was a problem and that is why the new ones are made so much better and stronger.

 

[Nwatson99]

Okay folks got an update.
I replaced the coils on Sat, I was able to mow 2/3rds of the yard without a single hiccup.
Since then I spoke with the dealership again wanting to speak to the regional John Deere manager since I should not have had to do anything other than standard maintenance on this machine.
The dealership contacted the regional manager on my behalf and then contacted me again stating this man wants to speak to me about my problems, so hopefully this gentleman will contact me and something would be resolved with these issues I am having.

Thus far since May of this year I have replaced:
Drive Idler pulley
Drive Idler pulley bracket
Drive Belt
Fuel Pump
Coils
Spark plugs

Routine Maintenance items I replaced and really did not have to, just trying to get the mower back to 100%
Inner and Outer Air Filter
Fuel Filter
Inspected all fuel lines

Oh and during my project of replacing the coils I discovered three other issues with the mower, I explained to the dealership what I found and I was told not to say anything until the JD rep calls me.