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I've got a John Deere x738 with 60 hours on it. About two weeks ago on start up I could tell it was different. The engine vibrated a lot more and the engine seems to be misfiring. When the engine starts its fine, but about 10 seconds after startup it beings acting this way. It clears itself up after about a minute or two. This does not happen if the engine has already been running and is restarted. The machine only runs on ethanol free gas and is kept in an attached unheated garage.

Things I've done already:
- oil and oil filter change and used Mobil 1 synthetic 10W-30 (old oil was John Deere version and very black and only in the machine for 50 hours)
- charged the battery (it was fine though)
- disconnected the battery and reconnected the battery (to possibly reset any electrical problems)
- checked hoses and wiring (saw no issues)
- added Sea Foam (can't hurt)
- changed fuel filter
- changed air filter and prefilter
- changed spark plugs

When I changed the spark plugs I saw they were in terrible shape, completely black and wet (see pics). It's at the dealership now but I am afraid they are going to say nothings wrong. Has anyone experienced anything similar to this?
 

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Need to know some things, tractordata says efi, but the engine does have a carb variant, so is this carb or efi, second is the ignition magneto or electronic ignition according to the engine manual from Kawasaki.

These are the places to look: Ignition is not working on that side, or EFI is injecting to much, or valve issues

Ignition: check for spark, bad plug or wire, bad magneto or firing circuitry on that side.
EFI: Bad injector (stuck open), Bad EFI module, bad connections/grounds.
Valve issues on that side.

Tractordata list engine as FD750D which acording to the Kawasaki manual is the carb/magneto engine, The EFI engine model number is FD791D and has the EFI and the electronic ignition.:dunno::banghead:
 

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Spark plugs are best read after the engine has been running for an extended time. Even a properly tuned engine can show some dark plugs if the thing has been started and stopped before warmup a few times.
What were the conditions of operation prior to removing your plugs?
 
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With only 60 hours should be under warranty.
 
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Your model should be EFI. If the new plugs didn't fix the problem it could be a bad plug wire.
The old plugs look loaded up from too much fuel. Short run cycles can also do this.

Seeing the dealership already has the tractor. They should be able to sort it out.
 

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Do you start the engine at full throttle or at least 3/4? Mine did the same thing and someone here (maybe HD Dude) said to try starting it at full throttle and let it run for a period of time before you throttle down. It worked.. My X738 would load up pretty bad and start spewing black soot and blue smoke starting it at low throttle.. I too changed my plugs, oil (but my oil was not dark at all it looked brand new) gas filter, everything you normally would do at the change of seasons. My plugs never looked like that though. I hope your dealer finds your issue, those are great little machines and worth their weight for sure. You have a lot of smart guys here to lean on for advice. One more thing, let the fuel pressure build up when you turn the key to on until you hear the pump stop then turn the key to start.
Jeff :hi:
 

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Thanks for all the comments. Mine is the fuel injected version. I didn't notice any stalling during the spring/summer/fall. It only started happening when it was cold out, but I do keep mine in the garage. Since both plugs look similar, I would imagine it is a systematic problem though. No plugs should look like that, hopefully I can report back something useful from the dealer. Thanks all.
 

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Thanks for all the comments. Mine is the fuel injected version. I didn't notice any stalling during the spring/summer/fall. It only started happening when it was cold out, but I do keep mine in the garage. Since both plugs look similar, I would imagine it is a systematic problem though. No plugs should look like that, hopefully I can report back something useful from the dealer. Thanks all.
I forgot to mention it was during the cold seasons mine did load up not n the warmer months.. And mine is also EFI controlled and garaged but not heated. . Good luck.
 

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I also have the similar issue with my x738, and stored inside but not heated, yet. It only does it when it is colder, runs rough and smokes for about a minute then runs like a champ. However, I only have 8 hours on it. I previously had an x730 and didn't have this issue, but also had no reason to use it when it was colder out. I just let mine warm up for a couple minutes before using it. Having said that, I am with you all in thinking that these should not spit and sputter on startup. It's EFI, should fire right up and run smooth. Reminds me of a diesel when its cold out.

Also, to my knowledge, the x710 is the only carb engine in the lineup. All the others above that are EFI.

Curious to see what the dealer says about yours. If they find an issue, I'll be taking mine is.
 

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Interesting, yours is the second one on any forum to report a bad fuel pressure regulator on EFI gas models. Keep us posted, I would like to know the range of pressure it was swing up and down to. Make sure they put that into the repair, not just bad fuel pressure regulator.
 

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So the shop called today and said:
- leak down test good
- compression test good
- sensors good
- fuel line pressure good
- fuel pressure regulator not good

They've ordered the part and will put it in on Wednesday and retest.
Thanks for this info, it's good to know what to look for in the future.. Let us know how it runs when you get it back.. Jeff :hi:
 

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Soooo the shop called and said the fuel regulator didn't fix the problem. They have looked it over but are at a loss and our now referring it to Corporate. Hope they find out what the problem is. Been 3 weeks now...
 

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Not sure if this is the issue but on my X585 the fuel pump slipped off the end of the fuel line. It would spray fuel into the end of the hose in the fuel tank. This would initially give the proper fuel pressure when the ignition was switched on and then the pressure would drop off. They said they thought the regulator was bad. What were the symptoms that made them think that?
 

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Soooo the shop called and said the fuel regulator didn't fix the problem. They have looked it over but are at a loss and our now referring it to Corporate. Hope they find out what the problem is. Been 3 weeks now...
Sorry to hear this EL, keep your fingers crossed it's something simple, what ever happened to an engine, spark, gas and start her up!!!!! Good old days, now,,, ?????:dunno: Old corvette, tune ups were a snap, new corvette, don't even think about it! You get the analogy.. Good luck with this issue and please keep us informed. Thanks TJ
 
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Unfortunately I spoke with the service department phone person not the tech. But it sounds like the tech was just going by a process of elimination. I imagine the tech was assuming it was getting too much fuel and the other possible factors checked off fine so he changed the fuel regulator.

I'm going on the 4th week without my tractor and I'm getting a little upset. Not at the repair shop, just the situation. At some point I will be saying replace the engine or give me a new unit. I assume lemon laws cover stuff besides just cars.
 

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It's weird that myself and other people are having the same issue though, and there isn't a TSB or something about it. And like I previously stated, I didn't have this issue on my x730. But I also didn't use it when it was cold. And it's the same motor as the x738.
 

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It's weird that myself and other people are having the same issue though, and there isn't a TSB or something about it. And like I previously stated, I didn't have this issue on my x730. But I also didn't use it when it was cold. And it's the same motor as the x738.
The sputtering and such is pretty common with these. Like I said; I crank it up (3/4) before I start and it does just fine but I still don't like powering up at that rpm right off the bat. I don't care what anyone says. But unfortunately the book says so.. and it does work, but obviously not for all.. It sucks EL is without his machine all this time, that's just not right.. This try this and try that is BS. MY blood pressure would be up there at this point in time.... It's not an atomic accelerator, it's a friggin small gas engine!:nunu: that's a gear grinder and I'm not even on the right thread!
 

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Unfortunately I spoke with the service department phone person not the tech. But it sounds like the tech was just going by a process of elimination. I imagine the tech was assuming it was getting too much fuel and the other possible factors checked off fine so he changed the fuel regulator.

I'm going on the 4th week without my tractor and I'm getting a little upset. Not at the repair shop, just the situation. At some point I will be saying replace the engine or give me a new unit. I assume lemon laws cover stuff besides just cars.
That is working under the assumption that the engine is the issue.

EFI machines can be pretty touchy to the wrong fuel pressure. It sucks when they just play the process of elimination game. It means for slow work because they try a part, it doesn't resolve the issue and they are sitting there waiting on the next part to come in. Sometimes that adds days between each attempt at fixing the issue.

If it comes to it, yes most states have some lemon law process. It might vary by state but I think around here I want to say it takes 3 separate visits with the same issue. One other option might be Green Promise. Not sure what the dates are for you. I think it is normally only 30 days but some areas they extend it to the spring because you may not have a chance to buy it. For instance when I bought my ZTrak in Jan a couple years back the Green Promise lasted until April or something like that.
 
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