# Zetor won't restart for 20 min after stall



## ZetorZip (Dec 12, 2007)

hi folks, I have a Zetor Zebra that won't restart for 20 minutes after a stall. it will turn over, but no chance of starting for about 20 minutes. not that I stall that much, usually only when the rotary cutter gets caught up on thick brush. but now that the weather is cold, it does not like to start, and if it starts to engage but doesn't, now I have to wait 20 minutes to try again! I don't know jack about engines, but I am learning. any suggestions on where to start looking for the problem? thanks!


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## Live Oak (Dec 22, 2003)

Welcome to Tractor Forum ZetorZip. Sorry to hear you are having some problems with your tractor. 

I would start at fuel cap or fuel vent to ensure the tank is not drawing a vaccum due to poor or no venting. Ensure the fuel cap or tank vent is open (no mud daubers) 

Is the fuel sump pickup at the bottom of the tank clogged or partially blocked with crud or other object? Ususally there is a screen or sock that can be obstructed with crud. 

Is the fuel filter clogged? If it has not been replaced in a long time, now might be a good time to do it or at least open the bleed vent screw/nut & verify good fuel flow. 

Does this tractor have a fuel transfer pump? If so is it working properly? Most tractors have a gravity fuel feed but some have a transfer pump. You have to look at the system and or your owner's manual to get an idea. Usually breaking the fuel line open coming out of the pump and turning the engine over to observe fuel being pushed out is a reasonable verification.

Is the injector pump functioning properly? Try breaking torque on the fuel lines at each injector so that are not completely off but very loose. Now turn the engine over several revolutions until you see a good spray of fuel from each fuel line. This would indicate the injector pump is OK. If no spray or weak spray, either the pump is bad or is not receiving a good fuel supply. 

If you suspect the fuel lines and or system may be clogged or not free flowing; it may be wise to remove ALL of the fuel lines and blow each one out with compressed air. 

At the same time you should drain the fuel tank and inspect the fuel sump pickup for any dirt, crud, or contamination and clean it out and blow out the fuel pickup with compressed air.

Blow out the tank vent with compressed air. 

Any one or combination of these areas could be causing your problem. 

I am sure some other members will jump in with some good ideas to check as well but hopefully this will get you started. 

Good luck and let us know how things go. :cheers:


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## wass (Jan 3, 2007)

I'm thinking you hit just about everything, although Mr Zetorzip might be learning a few new words before he's done. If it's any consolation, I spent a whole summer once with about the same problem before I found a small chunk of cotton-looking fuz in a banjo fitting at the primary fuel pump.


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## ZetorZip (Dec 12, 2007)

thanks for the great suggestions guys! now I have a checklist to run through. I am sure it is not the fuel cap ventilation, the original is long gone and it had a slightly loose fitting substitute over it when I got it (used). I was thinking about replacing the fuel filter, but the Zetor dealer only carries entire fuel filter assemblies. I'll have to pop it out and take it into town with me one day and see if I can find something comparable. I found the oil filter stock on the shelf at CarQuest. Other than checking the fuel sump pickup, yup, I am going to be learning some new words and tractor anatomy. But it sounds straightforward starting at the tank and checking each spot downstream for flow. I like these little challenges though, that's how I am going to learn what makes this (my 1st tractor) tick. One more quick question - if it is some kind of obstruction in the fueling system, (1) why is it only a problem after a stall and not all the time, and (2) why does it get better after 20 min? Weird, but interesting. cheers


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## Live Oak (Dec 22, 2003)

This is purely speculation & guess on my part but perhaps as the engine stalls the injector pump governor attempts to maintain rpm by continually adding more fuel up to its max. allowable. If something such as the fuel filter were clogged or fuel pump bad, this could deplete the fuel system of fuel or vaccum lock it until enough fuel could gradually flow bad up to the injector pump feed line. Could also be a problem with the injector pump. Definitely sounds weird to me as well. 

Hopefully more folks will reply and take a swing at this with more info.


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## chrpmaster (May 5, 2004)

if the fuel system is partially clogged the engine will stall from lack of fuel. If the clog is still in place then it takes 20 mins for enough fuel to get by the clog to start and run again. I have the same problem on a little MTD mower I have. I don't use it enough for it to bother me much but one time as a quick fix I blew air up the fuel line into the tank. There was some crud stopping the fuel flow, probably at the bottom of the tank, and the air pushed it out of the way temporarily for me to finish mowing. Of course I still haven't gotten back to it to remove the tank and clean it out. This would also explain your situation and how your tractor can start well and run for various lengths of time before the crud blocks the fuel flow. Thats where I would look first expecially since you said the cap was a loose replacement. Just a little gunk goes a long way!

Andy


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## ZetorZip (Dec 12, 2007)

Hi guys, happy holidays! I just wanted to update you on the Zetor situation. The inside of the fuel tank looked fairly clean, so I followed the fuel line out the bottom to what I assume is the fuel pump. It seems to have an adjustable valve on it, but I don’t know what it changes or how it should be set; it seems to be cranked all the way down. From there, the line goes to the fuel filter, which looked pretty bad when I opened it. I checked with every auto parts store and tractor dealer around, and no one had a suitable replacement. I found some Zetor parts dealers online, but most don't have Zebra parts. The one that did doesn't sell the fuel filters separately, I would have to buy the entire fuel filter assembly! So rather than buying an entire assembly every time I want to change the filter, I was thinking I might pop an inline fuel filter in before or after the existing assembly, which I would leave empty. My question is, can I do this, and does it matter if it goes before or after the existing assembly? I ask because there are other lines on the assembly that I don’t know what they do. There’s an obvious line in, and one out that goes to what I assume is the carb. But there’s a third one that goes directly back to the fuel tank. And from the carb, there’s another fuel line that makes 2 stops across the top of the engine before heading back into the fuel tank. Long story short: I would appreciate any advice on what the valve is on the fuel pump and how it should be adjusted, what is the line from the fuel filter back to the tank, what is the line from the carb back to the tank, and can I put an inline fuel filter in before or after the existing assembly? thanks! happy new year all!


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## Live Oak (Dec 22, 2003)

What model Zebra do you have?


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## ZetorZip (Dec 12, 2007)

Zetor Zebra 2040, http://www.tractordata.com/td/td1673.html. 
I was told it was a 1993. thanks!


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## Live Oak (Dec 22, 2003)

When you say carb, I think you meant injector pump? There will be pressure and return lines. You will need a diesel fuel filter, not a gasoline filter. Gasoline filters do not filter down to as small as a diesel filter. I will do some looking around online and see what I can find as far as filters for your tractor.


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## ZetorZip (Dec 12, 2007)

thanks TF Admin. you can clearly see I don't know my engine anatomy. can you recommend a good online link to get me up to speed on basic parts and functions? I appreciate your help in finding the filter, and continuing to help me learn. cheers


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## Live Oak (Dec 22, 2003)

Here are some links loaded with info.

http://en.wikipedia.org/wiki/Diesel_engine

http://www.free-ed.net/sweethaven/MechTech/EngineMech/EngMech01_TOC.asp

http://www.engineersedge.com/power_transmission/engine_fuel_system.htm


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## ZetorZip (Dec 12, 2007)

awesome. what I thought was the fuel pump is actually the primary filter I think, and the valve I was asking about must be the relief valve, which I now assume should be in the cranked down/shut position during normal operation. I will have to check for a drainplug so I can let out any crap that has accumulated on the discs. I'm still not quite sure why there is a line from the secondary fuel filter back to the fuel tank, but I think the line that goes over each cylinder and back to the tank must be connected to a relief valve so excess fuel from the injection pump can get back to the fuel tank, and/or it helps with cooling the injectors. neat. of glow-plugs, block heaters, etc., what is the easiest thing for a novice to retrofit to help with cold weather starts? thanks


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## ZetorZip (Dec 12, 2007)

update: finally located a replacement fuel filter element ($30 with shipping, but not many options). that fixed the 20-min-delay-after-stall problem. now I can stall it and immediately start it back up. which is good, because oddly it seems to be more reluctant to start now and stalls a lot at startup (but I should note that it is very cold). and that valve I was asking about, turns out that when it is unscrewed all the way, it comes out as a hand fuel pump (getting the manual has helped alot!). doh! I was way off on guessing that one. but it was handy for bleeding the lines after the filter replacement. I also discovered a 'decompressor lever' that holds the valves open for a given number of revolutions at startup, supposed to be helpful in cold weather, but I can't say that it makes an obvious difference. oh well, one step at a time, it's been a good learning process. I have another question, this one about hydraulic fluid. I have been tracing the hydraulic lines trying to figure out what is connected to what. looks like there is a pump on the front of the engine that runs the loader. and it looks like there is a separate system that runs the 3-pt and power steering. the 3-pt/PAS has a filter in the bottom of the tank, but I don't see a filter anywhere for the loader - is that normal? and for the 3-pt/PAS system, what kind of fluid should I be running in there? do I have to run PAS fluid, or can I use generic tractor hydraulic fluid like in the loader system? thanks


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## Live Oak (Dec 22, 2003)

It is not normal for the FEL to have a filter specifically for it. Consult your shop manual or owners manual about the proper or preferred hydraulic oil. In most cases most tractors use a transmission hydraulic fluid that you can buy at a variety of places. You will find that the Walmart brand tractor hydraulic fluid is the cheapest (generic). Most of Walmarts oils are manufactured by Shell for Walmart. You will have to decide if you want to buy the cheap stuff or pay twice as much and go with the name brand. I used it in my Kubota L245 and it worked just fine. I use the John Deere stuff in the 4410 but I will be using Shell Donax next change out. Not ALL tractors use this type of oil so verify what you need.


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