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Discussion Starter #1
Hello,

New to MTF and found it by searching for a solution to my problem which is the engine almost dies after first time starting when cold and runs very rough after restarting after a breif shutdown of a few minutes. This has been getting gradually worse over the last 2 years to the point where it runs at full throttle but idling down the governor is just up and down and can even backfire.
The only way I can improve the performance is to clean the air cleaner but this helps just slightly. I run regular gas, not ethanol, I keep the radiator clean with a blowgun removing the screen etc. I have replaced the FF,AF and plugs with no change. I wait until the fuel pump stops running before starting. The only thing I haven't done is to check fuel pressure or changed any of the sensors which I don't know how to check. Have also checked fuel cap to ensure vent is open. I'm wanting to guess it's the oxygen sensor or something like that which controls the FI system.
The temp runs around the mid section range.

Any ideas???

Thanks in advance, Paul
 

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Discussion Starter #2
I found that there is also a filter in the fuel tank? If this is true, maybe I should pull the fender and check this and also the fuel pump and lines. Where could a person pickup a economically priced pressure tester?
 

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Tractor Nut
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My '03 X585 did this while under warranty. It was sporadic at best and I could never actually duplicate it for the dealer. Eventually what my dealer did for me was replace my fuel pump and they also did a software update on the computer that supposedly would allow the engine to run a little richer for a limited time after startup. What they did seemed to have helped me. I'd be interested if EngineTech has heard of this.
 

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I am interested to. I noticed mine was surging at part throttle the other day. I opened the hood and watched the governor move back and forth slightly while just sitting there with no load. I start mine with the throttle slightly less then half or it will surge and can die when first starting.
 

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My Kohler 20 HP Verticle shaft surged after the engine had time to break in... I adjusted the air screw on the carb and it stopped it from surging....
 

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Discussion Starter #6
I am interested to. I noticed mine was surging at part throttle the other day. I opened the hood and watched the governor move back and forth slightly while just sitting there with no load. I start mine with the throttle slightly less then half or it will surge and can die when first starting.
Thats how this all began a couple years ago and steadily getting worse but especially when it is at normal temp or just above, in fact it has almost died completely on a hot day, sputtering and backfiring. The fuel pressure should be at least 28 psi I have read and should hold that pressure for a minute at least after shutting down if I understand correctly. Anything less would indicate a bad fuel line or fuel pump. Will buy or borrow a guage tomorrow and check it out tomorrow evening and let you know my results.

Thanks to everyone who replied.

Paul
 

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I have a '05 x485 that after mowing on a hot day and on restart it will surge. My dealer has checked out my two tractors and said that it is nothing to worry about. Like Cable gei said it just doesn't have enough rich gas at start up.
 

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Checked my fuel pressure and it only reached 20 psi and immidiately dropped down to 5psi then on down to 0. Called 2 dealers today and 1 service guy was very helpful on the phone so will call him tomorrow to see if this is normal. I believe I have a line leaking in the tank or bad fuel pump. Hopefully its nothing to do with the electronic controlled portion of it. Does anyone know how to check the codes????

My bad symptom is after I mow for say 1/2 hour, shut it off and go back 5 to 10 minutes later, it will hardly start, and run smoothly unless its at full throttle. Anything less, the second you put it to 3/4, 1/2 or a 1/4 throttle it sputters, surges just terribly. And it will do it without shutting it down also.
 

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Checked my fuel pressure and it only reached 20 psi and immidiately dropped down to 5psi then on down to 0. Called 2 dealers today and 1 service guy was very helpful on the phone so will call him tomorrow to see if this is normal. I believe I have a line leaking in the tank or bad fuel pump. Hopefully its nothing to do with the electronic controlled portion of it. Does anyone know how to check the codes????

My bad symptom is after I mow for say 1/2 hour, shut it off and go back 5 to 10 minutes later, it will hardly start, and run smoothly unless its at full throttle. Anything less, the second you put it to 3/4, 1/2 or a 1/4 throttle it sputters, surges just terribly. And it will do it without shutting it down also.
How many hours on your tractor? I don't know a pressure spec on the fuel system.
 

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My X300 started doing that, too. Finally, it began running on only one cylinder. I replaced that coil and it now runs great and no surging!!
 

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This sounds identical to my problem. Mine only did it after mowing for a while to where it was good and hot. Shut it off, come back and restart in 10 minutes or so, and it wanted to surge at low and medium throttle. Full throttle always smooths it back out.
 

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TT a dealer and said psi should be 25 to 27, any more or less would indicate a bad fuel line or pump. Pulled the rear bodywork tonight and tested directly off pump and still reading 20 psi so will pull the pump and check the line inside tank. If thats OK will replace the pump which sells for around 215 plus gasket and 13 for the wiring kit. The rear pops off pretty quickly really, can take pics if anyone is interested.
 

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TT a dealer and said psi should be 25 to 27, any more or less would indicate a bad fuel line or pump. Pulled the rear bodywork tonight and tested directly off pump and still reading 20 psi so will pull the pump and check the line inside tank. If thats OK will replace the pump which sells for around 215 plus gasket and 13 for the wiring kit. The rear pops off pretty quickly really, can take pics if anyone is interested.
Would like to see pictures.
There is a fuel regulator involved too. The fuel pump is supposed to pump 120ml or more for 3 seconds running ..which is the time it is supposed to run when just turning the key on without starting.
The regulated pressure is supposed to be between 24.9 ~ 26.4 with engine running at 3600 RPM.
Edit --> These are specs for my engine FD750D I assume your is similar
 

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I just had the surging problem on my 335 fixed. It's not fuel injected but the problem could be similar... mine had a vacuum leak on the intake manifold.
 

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Pulled the pump this morning and a hose had come loose off the pump. It was also starting to get soft so I replaced it and all is good now. I don't know how to make my pics smaller so anyone interested can PM me and would be happy to email them to you and maybe you could post them. Removal was pretty easy of the rear bodywork, 2 bolts on both sides in front of rear tires, the 2 rear bolts in the seat framework and 1 bolt which holds the grab handle on the filler tank side which holds a j piece that grabs the gas tank. Un plug the seat switch and rear light connector on right rear side and pull up and back and it comes right off. Need to take gas cap off also. The pump housing is fully exposed in top of tank which makes it nice. I also took the 2 front bolts off the seat bracket also but that wasn't necessary, although it was easier to handle without the seat. One thing I noticed was that the 5 bolts holding the pump in place was only slightly snug, theres a thick rubber gasket and it really only to nneds to keep gas from slushing out so suspect a person could get these too tight by accident and strip them out. Theres allot of grass buildup under there after 5 years! Also I used a blow gun to clean the fuel connections before disconnecting and also the electrical connections need dielectric grease on them. That's it!
 

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Here are some of the pictures. So if I understand the internal hose from the pump to the pickup assembly was loose basically causing the pump to leak out into the tank and not build pressure?
 

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Some more:
 

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Congrats on the repair PACABADA! Even though the tractors now have "modern" systems on them it always pays to check the basics!
 

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That connecting hose has those factory crimped clamps. I have had those leak in several automotive applications. I bet as the system ages and fuel ages that hose all the X700s that use this setup start to get loose. The pump/intake screen probably sits on the tank floor inside the tank so it will not fall away but the hose starts to leak internally and causes a pressure drop. I am under warranty and my surging is not bad but I think I may have the dealer check it out latter this fall but in the future I will check on this. Thanks for the pictures!:greendr:
 
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