[Chuck924]

Picked up my new mule pro mx from dealer last week. Ran it for 4 days, no issues, ran good, very happy with it compared to the 610XC’s I have had previously. Day 5 temperatures were a bit colder, and started running rougher, wouldn’t idle. Finally wouldn’t start at all. Called dealer, said it sounds like plug fouled, maybe I drove it without seatbelt causing it to load up and foul plug ( I told him no, but the. after the call remembered that I did do that...ooops). Said they would pick it up on Tuesday due to the easter holiday.. So Saturday I go out and get a new plug, stick it in, it fires right up and is running good, until Sunday, when it starts loading up again (carbon fouling plug) you could actually smell fuel a little bit. Still ran but wouldn’t idle.

Dealer picked it up Tuesday and called me Tuesday afternoon said they put a new plug in and its running good. I told him that I had replaced the plug over the weekend and it worked for a day before it started fouling out again. He said that the fuel injection is set and thats not the problem ( I dont know crap about fuel injection) Anybody have any ideas? I don’t want to get the thing back and keep going through this, I use it daily here on the farm and its a big inconvenience not having it.


Sorry for the long winded post, but I’m already frustrated

 

[Mule055]

Might try a hotter spark plug... seems to fix the issues on the older mule 610's that fouled plugs

NGK.com: Heat Range Conversion Chart

www.ngk.com

 

[Chuck924]

Might try a hotter spark plug... seems to fix the issues on the older mule 610's that fouled plugs

NGK.com: Heat Range Conversion Chart

www.ngk.com

Thanks for the advice, have had it back for 2 days now and still seems OK., if it starts loading up again I’ll try the next hotter plug.

 

[Jeremy-WI]

I would suspect fuel pressure, oxygen sensor, intake air temp/ coolant temp sensor as a FI system should never run lean or rich if it is functioning properly. The FI system with enrichen the fuel mixture in cold weather similar to using a choke on a carb. I ran my Pro MX in below 0 weather plowing snow and haven't had any issue with it and I bet the rev limiter you hit without the seat belt fastened restricts fuel and shouldn't foul a plug

 

[Zebrafive]

Or the seatbelt "Nanny" may cut the spark?

 

[Chuck924]

I would suspect fuel pressure, oxygen sensor, intake air temp/ coolant temp sensor as a FI system should never run lean or rich if it is functioning properly. The FI system with enrichen the fuel mixture in cold weather similar to using a choke on a carb. I ran my Pro MX in below 0 weather plowing snow and haven't had any issue with it and I bet the rev limiter you hit without the seat belt fastened restricts fuel and shouldn't foul a plug

Thats what I was thinking, something wrong with fuel system , but Allegedly they checked the fuel system and said everything was OK, so I will just have to wait and see. I have bought several mules from a dealer thats 10 minutes away from me, but the family that owned it forever sold the business and the new people cant seem to find any good mechanics, which is why I bought this mule from a new dealer. It doesnt make any sense but I will have to wait and see.

 

[Jeremy-WI]

Or the seatbelt "Nanny" may cut the spark?

I hope not as that would cause big troubles for the catalytic converter

 

[alleycatter]

Thats what I was thinking, something wrong with fuel system , but Allegedly they checked the fuel system and said everything was OK, so I will just have to wait and see. I have bought several mules from a dealer thats 10 minutes away from me, but the family that owned it forever sold the business and the new people cant seem to find any good mechanics, which is why I bought this mule from a new dealer. It doesnt make any sense but I will have to wait and see.

When I bought my Pro MX the dealer said the factory sets it at rich for the break in and there's a good chance that the plug will foul.

 

[Mulemx21]

Picked up my new mule pro mx from dealer last week. Ran it for 4 days, no issues, ran good, very happy with it compared to the 610XC’s I have had previously. Day 5 temperatures were a bit colder, and started running rougher, wouldn’t idle. Finally wouldn’t start at all. Called dealer, said it sounds like plug fouled, maybe I drove it without seatbelt causing it to load up and foul plug ( I told him no, but the. after the call remembered that I did do that...ooops). Said they would pick it up on Tuesday due to the easter holiday.. So Saturday I go out and get a new plug, stick it in, it fires right up and is running good, until Sunday, when it starts loading up again (carbon fouling plug) you could actually smell fuel a little bit. Still ran but wouldn’t idle.

Dealer picked it up Tuesday and called me Tuesday afternoon said they put a new plug in and its running good. I told him that I had replaced the plug over the weekend and it worked for a day before it started fouling out again. He said that the fuel injection is set and thats not the problem ( I dont know crap about fuel injection) Anybody have any ideas? I don’t want to get the thing back and keep going through this, I use it daily here on the farm and its a big inconvenience not having it.


Sorry for the long winded post, but I’m already frustrated

Did you ever figure it out. I got mine home and only put 7km on it and it won't stay running at all. Put a new plug in and no improvement.

 

[Houska]

In case anyone finds this: my in-laws had this trouble with their 2019 Mule MX Pro. Trouble was their usage pattern: due to health troubles, they were using the new mule only for very short trips, 500' up/down a hill. When health improved and started driving for several miles, fouling stopped.

 

[Chrishall1971]

I’ve had the same issue for a year now when the temps drop below 40 degrees the mule starts fouling plugs every 7 days. Took it to the dealer and they said the same answer as one above that the engine is not designed for short trips and must be run hard to get it up to temp to keep the plug from fouling. I’ve also been told by other dealers to not fill the oil to the top mark and also run a hotter plug. All BS. I run a farm so that’s all I do is stop and start as I make my rounds so to me there should not be an issue within its realm of operation. If Kawasaki is selling this as a workhorse then there should be a disclaimer when sold about the issue.

 

[83Shovel]

I’ve had the same issue for a year now when the temps drop below 40 degrees the mule starts fouling plugs every 7 days. Took it to the dealer and they said the same answer as one above that the engine is not designed for short trips and must be run hard to get it up to temp to keep the plug from fouling. I’ve also been told by other dealers to not fill the oil to the top mark and also run a hotter plug. All BS. I run a farm so that’s all I do is stop and start as I make my rounds so to me there should not be an issue within its realm of operation. If Kawasaki is selling this as a workhorse then there should be a disclaimer when sold about the issue.

Agree. It ain’t a two stroke moto cross machine.
I wonder what their definition of “must be run hard” is???
Would bringing the R’s up to a certain point just sitting in neutral help any.
Not a real valid answer to the problem, but run that sucker in low range a good bit ever time.

Another reason why I don’t understand how a speedometer is of any value over a tach in an off road machine. Actually I think it’s senseless for anything with a gas/fuel powered engine that you drive or ride not have a tach.

My dealer also told me that if I experienced any hard starting to go to a hotter plug. Hasn’t happened yet. 2023 Mule Pro MX at 17 hrs.

 

[Chrishall1971]

I’ve been running the NGK CR7e’s per the dealer instruction with no luck. mine has about 400 hours on it now and currently at the dealer for the issue. I handed the mechanic a bag full of foul plugs- you should have seen his face, lol! Anyway yeah the mechs can do anything to remedy the issue and you have kawasakis so I’m gonna talk to the sales manager when I pick it up to see what they can do.

 

[Chrishall1971]

Did you ever figure it out. I got mine home and only put 7km on it and it won't stay running at all. Put a new plug in and no improvement.

the dealership called Kawasaki and their solution was not to drive it for short stop and go trips, if you have to run it in low range.

 

[Catoctin]

I just did my 120 mile service at a local dealer. Got unit back and it was leaking on my concrete floor in my barn. They took it back and said it was just spillage in the skid plates that they cleaned up.

I had asked about them running rich b/c of reading this thread previously. They said that Kawasaki actually makes things run lean b/c of regulations and not to worry. It sounded kind of rich to me since I got it. They dropped it back at my house and my wife parked it in the barn. Couple days later I go to turn it around b/c she doesn’t like backing it in and it won’t start. I go and buy a couple new plugs, put one in and it starts. Old plug was very fouled. Drove it around my yard for 5 min and parked it. Literally had smoke coming out of the exhaust and it was making heat cracking noises much more than normal. I can imagine there was some extra gas from it being kind of flooded but it’s crazy to me how hot the thing got after 5 min. It has never done that before. Thoughts on the new running hot thing?

Any suggestions on how to get this addressed by Kawasaki so that we don’t just keep having to put new plugs in. Seems crazy that you would have to run it longer to keep it from fouling as its supposed to be a work thing around property where you will do short trips all the time. Its not really a cruiser thing.

 

[83Shovel]

I would think the most logical fix would be to re-tune it via the gizmo that determines air fuel mixture. Lean it out some.
No different than re-jetting a carb but requires telling the compooter who needs what.
Only thing else that could come in to play would be tweaking whatever they do to burned/unburned exhaust gases. And or the emissions crap. Maybe.

But. I don’t know baby shit from apple butter about tuning fuel injected machines.

 

[Chrishall1971]

I just did my 120 mile service at a local dealer. Got unit back and it was leaking on my concrete floor in my barn. They took it back and said it was just spillage in the skid plates that they cleaned up.

I had asked about them running rich b/c of reading this thread previously. They said that Kawasaki actually makes things run lean b/c of regulations and not to worry. It sounded kind of rich to me since I got it. They dropped it back at my house and my wife parked it in the barn. Couple days later I go to turn it around b/c she doesn’t like backing it in and it won’t start. I go and buy a couple new plugs, put one in and it starts. Old plug was very fouled. Drove it around my yard for 5 min and parked it. Literally had smoke coming out of the exhaust and it was making heat cracking noises much more than normal. I can imagine there was some extra gas from it being kind of flooded but it’s crazy to me how hot the thing got after 5 min. It has never done that before. Thoughts on the new running hot thing?

Any suggestions on how to get this addressed by Kawasaki so that we don’t just keep having to put new plugs in. Seems crazy that you would have to run it longer to keep it from fouling as its supposed to be a work thing around property where you will do short trips all the time. Its not really a cruiser thing.

Wish I had a good answer other than what I’ve written before. Kawasaki basically gave me the “ not our problem“ answer with the warm up the engine with medium RPM’s prior to driving and if you’re driving short distance use the low range solutions. since I got mine back and using those suggestions I have not fouled a plug though. I do make it a point to drive at top speed for a good distance to burn the crud off the plug. I will be trying an E3 E3.38 plug which replaces the NGK CR7E,8E and 9E plugs. This plug should burn hotter. Just FYI the motor in the Mule is made my Kimco under license of Kawasaki, my mech said they cannot hook their computers up to it and adjust the fuel mixture do to this.

 

[Catoctin]

Wish I had a good answer other than what I’ve written before. Kawasaki basically gave me the “ not our problem“ answer with the warm up the engine with medium RPM’s prior to driving and if you’re driving short distance use the low range solutions. since I got mine back and using those suggestions I have not fouled a plug though. I do make it a point to drive at top speed for a good distance to burn the crud off the plug. I will be trying an E3 E3.38 plug which replaces the NGK CR7E,8E and 9E plugs. This plug should burn hotter. Just FYI the motor in the Mule is made my Kimco under license of Kawasaki, my mech said they cannot hook their computers up to it and adjust the fuel mixture do to this.

Thanks for this info. I plan on calling the selling dealer and local dealer to see what they think after the holiday. I’ll let you all know what they current responses are.