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paul03_gw

JD X500 almost stalls when PTO is put on

paul03
13 years ago

With the engine running at full speed and the PTO is put on to start the cutting deck, the engine RPM will lower to almost a stall and then quickly go back to fast idle.

A friend of mine has the exact JD model and year (2010), and his JD X500 maintains the same RPM speed when he puts his cutting deck on with no slow down in RPM. Does this mean that my JD is running too lean?

I noticed that there is no carburetor adjustment to correct for a lean or rich mixture.

This tractor is just 3 months old and was doing this from day one.

Comments (26)

  • justalurker
    13 years ago

    First thing to try...

    Disconnect the belt that runs from the engine pulley and drives the mower deck.

    With that belt removed check each quill (mandrel) and make sure each one turns smooth and easy. A binding quill will create that exact problem.

    If that is not the problem then surely your 3 month old X500 is within the JD 48 month-5 year warranty so call your dealer.

  • wheely_boy
    13 years ago

    The previous suggestion is a good one. I would just add that this problem will also generate a lot of heat so therefore the offending components will get smokin' hot when run for just a few minutes.

    You might also pull the deck to see if you picked up a rope or something.

  • squirejohn zone4 VT
    13 years ago

    My 2010 JD X500 does the same thing. I seem to recall seeing on another forum that this is normal. Now I'm begining to wonder asthe rpm's in my previous owned JD316 didn't drop noticeably when the PTO was engaged.

  • justalurker
    13 years ago

    If engaging the mower on an X500 at WOT drops the engine speed to almost stalling that is not normal regardless of what you read on any forum.

    An RPM drop and recover sure, but not an RPM drop to almost stalling.

    Something is wrong and if you lack the diagnostic ability or knowledge to find and correct the problem then get your X500 to someone who does.

  • mownie
    13 years ago

    I concur with justalurker.
    While the symptom may seem to affect a significant number of machines (supported by anecdotal "evidence"), that does NOT make it "normal".
    Until John Deere publishes a statement that this characteristic is unavoidable for some reason (EPA emissions standards compliance??) or other technical reason...........I believe an engine running at "no load, high idle" should not suffer that much RPM drop when engaging the PTO.
    There may be some reasons other than a problem with the engine causing this, such as the PTO clutch being "too quick" or grabby on engagement which applies the PTO load too fast for the engine governor to react.
    Whatever the "problem" is, it does seem to affect a number of the machines.

  • justalurker
    13 years ago

    John Deere X500 Operator's Manual says "Always operate at maximum throttle speed when mower is engaged".

    To be as clear as possible... maximum throttle speed is not fast idle, faster than idle, or the speed I choose.. It is, in the vernacular, WOT (wide open throttle).

    I have seen many posts on many forums where people who don't know what they don't know adopt the policy that they know more than the engineers and decide that half throttle or any throttle position other than WOT is more correct to engage an electric clutch then the specification set by the people who designed then tractor.

    With what the OP paid for his new X500 three months ago, and I have an X500 so I know what they cost, it amuses me that he has not already been back to his dealer to report this problem but rather brings the problem here where we are not authorized to do warranty work ;-)

  • mownie
    13 years ago

    To add clarification to my last post, "no load, high idle" is in fact Wide Open Throttle where the engine RPM is at the governor top limit.
    AKA "maximum governed speed, no load" and also sometimes called "high curb idle".

  • justalurker
    13 years ago

    Just a thought for the OP and others having this problem... if you don't get off the choke quickly and allow sufficient time for the engine to warm up before engaging the electric PTO you may be encouraging the problem.

    These little twins, both air and liquid cooled, need a little while to get up to working temp and can be cold-blooded especially with current emission requirements.

  • squirejohn zone4 VT
    13 years ago

    Maybe I should clarify my post above. When I engage the PTO to operate the mower the rpm's drop way way down but in no danger of stalling and recovers after only a second or two. This condition is the same whether the engine is "cold" or after mowing for a while.

  • justalurker
    13 years ago

    RPM drop for sure but not "RPM will lower to almost a stall" as the OP said and you said "does the same thing".

    Remember WOT is around 3200-3600 RPM and most JDs with Kaw twins I've put a tach on idle high at about 2000-2200 RPM so dropping 1000 RPM at PTO engagement may seem like a severe drop and probably more dramatic engaging a 54" deck than the smaller 48" deck, but dropping to almost a stall is not right.

    You ought to see the RPM drop on my X500 when engaging the 44" snow blower and then the 47" blower has more mass to spin.

  • greenhobby
    13 years ago

    You should be able to easily engage the blades or snow blower with the throttle at half. It will dip a bit and catch right up. If it stalls, then the carb is not running right. You should always mow / blow at WOT, but it should easily engage without stalling. I had this same problem with my GX345 and the dealer adjusted the carb so it doesn't stall under light load.

    -gh

  • doberman_2007
    13 years ago

    If you dont warm the engine for a few minutes it will try to stall when the pto is engaged my machine will duplicate it, we all get in a hurry. I have done it a few times . A simple pull of the deck will make sure the pullys run freely , make sure you have a grease gun handy , grease the bearings in the top of deck. Even when warm it will give a little rpm drop when the pto is engaged , but shouldnt try to stall...

  • squirejohn zone4 VT
    13 years ago

    Well I guess "almost to a stall" is a good description after all of what my X500 also does. It's not as though it seems to stall but rather like going from WOT to turning the key off and then right back on.
    I guess in either case this isn't normal, so in the Spring (don't use in winter) I'll check it out with my Dealer.

  • justalurker
    13 years ago

    squirejohn,

    If you mean that split-second hesitation at the exact moment you pull the PTO switch, sorta like a comma in your engine's tune, then that is normal.

    More a hesitation than an RPM drop and labored climb back up to full RPM... yes?

    When someone describes an RPM drop as "almost to a stall" experienced techs hear us that the RPM drops dramatically and that the engines labors to get back up to full speed. A longer happening(?) than you are describing.

    The problem with trying to diagnose something long distance or over the wire is that those trying to help has to rely on the knowledge to understand what the poster is trying to describe and their ability to describe it accurately in the terms the helpers can understand.

  • squirejohn zone4 VT
    13 years ago

    justalurker

    Thanks!

    That decribes it exactely; "split-second hesitation" and
    "comma" in engine tune.
    I'm glad to hear that's normal!

  • paul03
    Original Author
    13 years ago

    Let me clarify this problem of the RPM slow down to almost a stall when engaging the PTO. I allow the engine to warm up for 3 full minutes, then go to WOT and then pull the PTO. The RPM will drop down to about the speed as if the throttle was set at it's lowest level for about 1 second then instantly recover to it's WOT speed. I presented this issue to the JD dealer and was told that this is normal, that some tractors drop RPM more than others, in other words as long as it does not stall it's OK.
    And regarding the warm up period, the JD manual states that the warm up should not exceed 1 minute, and I will quote the manual "IMPORTANT: avoid damage!Unnecessary engine idling may cause engine damage. Excessive idling can cause carbon build-up and overheating", but a Kawasaki book that I have states that warm up should be about 3 minutes, which is what I do. Who is right, JD or Kawasaki?
    I want to thank all of you who have responded to this forum.

  • justalurker
    13 years ago

    One minute or three minutes... is that at both 3 degrees F and at 95 degrees F?

    Use your head... three minutes is not enough time to warm a piece of toast let alone a block of aluminum and a couple quarts of oil.

    There's idling and then there's excessive idling.

    Next time you start your X500 wait one minute then reach down and feel how hot (cold) the oil filter is. When the oil filter is warm so is the engine. I'll bet it takes more than three minutes cause it does on mine... especially in the winter.

  • tomplum
    13 years ago

    When you are comparing this to the like unit, you are talking same decks and no powerflo? "Warm up" is a relative term. It doesn't take long for the combustion chambers to heat up as opposed to the sump. Ambient temp can have an effect as Lurker said. One minute or three seems like politics to me. These engines meet emission standards which do have an effect on opperation. Things you have control over are fuel quality and freshness along with keeping the maintenance done. If adding a touch of choke lessens this, than you are correct- it seems to be acting lean. As new as this is, the dealer should check it out. And he would like to hear about it now rather than much later.

  • justalurker
    13 years ago

    Ambient temp also has a significant effect of fuel atomization... and the colder the air the denser it is.

  • paul03
    Original Author
    13 years ago

    The time of year all of this took place was from September thru October and the temperature range was between 85F for a high and 72F for a low, the tractor is not used in the winter.I have also tried a 10 minute warm up during that period which did not change the results. The people at JD do not recommend long warm ups, they still stress the 1 minute time run at half throttle for the warm-up period, which is what the operator's manual recommends, again we are talking summer and early fall operation.
    JD has found that long warm-ups have caused problems in some cases.

  • mownie
    13 years ago

    I think most of the rhetoric being passed out by JD or other "factory sources" recommending against "excessive warm-up time" are doing so at the behest of EPA to reduce "idle time emissions", and possibly some other reasons that are not related to the health of the engine.
    Specifically, I am referring to running an engine at high curb idle (WOT no load). An engine will happily, and healthily run its entire lifetime at that RPM and suffer no ill effects, but what practical use would that provide? NONE!
    Running an engine at its lowest possible curb idle (on the other hand) will cause lube problems in most of the moving parts and the life of an engine operated this way will likely be much shorter than if the engine had been used in heavy work but with proper maintenance.

    The suggestion to check the temp of the lube oil filter would indeed reflect the overall average temp of the engine crankcase, but a check of the exhaust pipe/muffler temp is a reflection of the temperature of the combustion chamber itself (but don't try to test it with your finger).
    A crude test of how fast the muffler (and combustion chamber) heat up might be done (for demonstration purposes) by simply "spitting" on the cold muffler and then starting the engine and timing how many seconds elapse before the liquid boils. (people who dip or chew tobacco should refrain from this demonstration :^)
    A warm-up period should not have to be much more than a minute or so (and we have come right back to square 1) past the point at which the muffler made steam from spit.

  • paul03
    Original Author
    13 years ago

    I would just like to add one final comment to this topic. After reading all the responses I received on this topic I realize that I have used an incorrect phrase to describe my problem. When the engine is at WOT and I pull the PTO the RPM's drop to near idle , or as Squirejohn has put it that the RPM drops "way way down", I should not have said that the engine almost stalls. Justalurker had stated that a Kawasaki engine at WOT revs at 3200-3600 RPM, and has an idle at 2000-2200 RPM. This is what must be happening that when the PTO is pulled the RPM drops to close 2200 RPM for 1 second and then immediately recovers to 3600 RPM without laboring. To me that 1000 RPM drop sounded like it was heading for a stall, but I was wrong. Mownie has added that this could be caused by a PTO clutch being "too quick or grabby on engagement" and this would explain why some tractors do this and others do not. JD had told me that this was not a problem, but I wanted to post this forum to see if others had a similar situation and I see that others have this condition. I would like to thank you all for your input, this has helped me to realize that a drop to near idle for 1 second is NOT a near stall situation.

  • justalurker
    13 years ago

    In the old, old days the phenomenon might have been described as a hitch in it's getalong

  • greenhobby
    13 years ago

    Just a thought, you also want to make sure that the deck zerks are well greased and maintained. Does it 'dip' with other attachments?

  • Sloggit1
    11 years ago

    Having had a X540 for 3 years I have had the same problem and found that the engine temperature is a factor. But I will say that it has actually made my engine stop by engaging the clutch. I have a 54" deck and in three years �3 clutch bolts have sheared off the last being yesterday. I was assured that a mod had been made after the last one sheared. It has sheared even when i have not had the clutch engaged I was just towing an empty garden trailer. So John Deere I'm afraid should own up to the obvious design error / problem and sort it out. I have done 340 hours on my X540 and having been an engineer all my life I have no doubt at all the fault lies clearly with the design or materials. One last point does this only happen with the 54" deck if so the clutch size / design should be different for a larger deck.
    All the best guys

  • justalurker
    11 years ago

    Clutch bolt failure on JDs is one of those problems that really pisses me off. It is not so rare but common enough that it's heard of.

    Not only is it annoying but in some cases engine or crankshaft replacement is required. At minimum the clutch and bolt are replaced.

    Under warranty it's an inconvenience for the owner but after the warranty expires... a BIG BUCK REPAIR BILL.

    You'd think that resolving the problem would be easy.

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