# Diagnosing Diesel tractors



## Rob30 (Nov 2, 2004)

I have a belarus 500. Ever since I bought it it has been hard to get started. It is taking literaly hours to get her stated. I usually hook the truck battery to it because I will drain the two big batteries on it. I believe it is a fuel leak problem, but can't find where it is leaking. The primer doesn't work very well, leaks bad when in use. After the tractor is started it will usually start as long as it doesn't sit for too long. I pull started it the last two times with my truck. When it starts it sputters with lots of white smoke like a diesel with air in the fuel. My question is where should I start looking for the leak? I believe it would be between the pump and injectors. A leak before the pump would not cause the hard starting. Also it seems to smoke alot from the pcv on top of the valve cover. I understand this is common in belarus tractors, but how much is too much? How can I check for worn rings? I have to get this fixed before winter. I don't know anything about diagnosing diesels. I need a crash course.


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## agmantoo (May 23, 2003)

A leak before the injector pump is just as bad for hard starting as one after the injector pump. Air in the system from the inlet of the fuel filters to the injectors will make for hard starting. All diesels are going to have some blowby. Some have a lot more than others. You can remove the injectors and take a compression test but you may disturb the seals on the injectors and often they are stuck, really stuck and you may need a tool to fit the injectors. I do not suggest doing the compression test at this juncture. What weight oil is in the crankcase? How fast is the starter turning the engine. It needs to be turned around 200 rpm to make enough heat to start. Have you tried to heat the intake manifold to see if the tractor will start. Be careful, do not set the tractor on fire. Have you ethered the engine, it may have an ether habit.


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## Old Vet (Oct 15, 2006)

Diesel engines have two things that will cause your problem. One is compression. You need to take a compression reading and see that is the reason. The second is a fuel problem. This may be a leak or a bad fuel pump. Either one will make your tractor hard to start and produce white smoke at startup.


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## Beeman (Dec 29, 2002)

White smoke indicates unburned fuel. Blow by at the breather at the top of the valve cover, hard starting and white smoke all seem to indicate plenty of fuel but low compression. As stated I would start with a compression test.


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## Ross (May 9, 2002)

Have you cleaned the air intake Rob? Does the oil pressure guage working and do you have oil pressure? Low compresion isn't always a big repair it might just need adjusting. My DB 990 was like that. How fast does the starter crank the engine? Never use ether BTW it'll seize a Belarus temporarily.


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## zant (Dec 1, 2005)

1.White smoke means water vapor-possible head gasket.
2.Black smoke means overfueling.
3.Blue smoke means oil blowby.
DO NOT use ether unless dealer says yes or owners manual says yes-ever see a twisted crank?
I had a crappy gen that would'nt start below 50degrees so I would take off air cleaner and put propane torch down intake-crank motor-fired right up.


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## Rob30 (Nov 2, 2004)

The starter turns slow in my opinion. I have been told it has two batteries and needs them. 
When turning over with the starter there is no smoke at first. It takes several attempts to start. Before strarting the first smoke is white, then it turns black as it starts to kick and then start. However the last couple times I could not get it to start. Very little white smoke would came out. If I can't start it with the starter I have jump started it. It will start blowing white smoke. Then black. It revs up and down like threre is air in the fuel. Then levels out. I can't imagine the compression is bad, because while jump starting it I was able to stop my truck dead when I popped the clutch in 4th gear. And I have a big truck. After it starts it runs fine, has lots of power, smokes more then my DB did, grey smoke. It has lots of power. The steepest hills won't stop her with the round baler on in 8th gear. Its hard to believe there is a problem after it starts.
I know belarus tractors smoke alot, use alot of oil (mine does), and leak every where. You know a belarus is out of oil when the leaks stop. 
Do I need a special compression tester for a diesel?


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## agmantoo (May 23, 2003)

yes, you need a special compression tester. The compression tester must be mounted to the head through the injector holes or on some through the glow plug holes. As I stated before, it is easy to damage an injector and its seal. Have a new set of seals PRIOR to doing the test. You need proper tools to get the injectors out without damaging them. You can wake up the devil if you are not properly prepared. Maybe you could get a diesel mechanic to drop by your place and do the test. I would verify that everything else has been eliminated before disturbing the injectors. Have you tried removing the return to tank line for the fuel and using a clear tubing for the task then observing to see it there are air bubbles in the return fuel when cranking? Heating the air intake will give the same effect as increasing the crank rpm, are you reluctant to do that? When you use the manual primer will the primer build up pressure as you pump? If so, while pumping real hard have someone to crank the engine and see if it will start.


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## Rob30 (Nov 2, 2004)

I always turn the glow plugs on for a bit before turning over the engine. But I will try warming the manifold. I was told a belarus won't start if the glow plugs are not used, even if the engine was already running. I will also get the batteries checked to make sure they are getting enough juice to the starter. I have looked through the entire fuel system and can not find any evidence of a leak. I will be replacing the primer pump to see if priming helps before starting. 
By the way Ross the guages do not work. I need to get at least the oil pressure, temp, and tach working.


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## agmantoo (May 23, 2003)

Have you verified that all the glow plugs are working? How long do you leave the glow plugs on and how soon after heating do you try to crank? Have you every tried to double the glow plug cycle by heating twice in succession? I s the oil on the dip stick gooey and globby? That is enough to impact the cranking RPM. You need to get the crank speed as fast as possible.


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## agmantoo (May 23, 2003)

Since the engine will start hot I feel the compression is good enough if you can get the tractor's air and fuel hot with the glow plugs and the crank speed.


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## haypoint (Oct 4, 2006)

You need two good sized batteries, either two 6 volt in series or 12 volt in parallel. If it turns too slowly, perhaps the starter is shot, check the brushes. In cold weather, I had to resort to a Delco starter. 
Glow plugs could be shot. Check them. With the key turned, but not far enough to engage the starter, wait 60m seconds. Now feel the ends of the glow plugs. They should be noticeably warm.

The primer is a simple device. It reminds me of a middle-school shop project. Take it apart and sand the rust out of the bore. Check the O ring, replace if needed. Make sure the check valve and spring are working.
Then, screw down the plunger and there shouldn't be any leaks.
To prime the Belarus, remove the bolt from the side or the injector pump. unscrew the pump top and pump until fuel flows from the bolt hole, replace bolt and screw down the pump top.


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## Old Vet (Oct 15, 2006)

Any diesel engine needs compression fuel at the right time and nothing else.So just check the fuel and spend allot of time wondering what it could be or do a compression test and see for sure.


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## Rob30 (Nov 2, 2004)

I will take abart the primer this weekend. What is the difference between the starter and a delco starter? Where would I find a delco starter?
I am sure the glow plugs work, becaure I can see the oil on the engine start smoking when I have attempted to start it several times. I'll check them all though. I am wondering if the batteries are not strong enough. I'll take the starter and batteries in to get checked.


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## Beeman (Dec 29, 2002)

Check voltage drop thru the battery cables, good chance you have a bad ground, dirty terminals, bad cable, all of the above.


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## Ross (May 9, 2002)

A Belarus shouldn't use oil as a design flaw. Mine never used a drop nor did it smoke unless it was in winter after a hard start and then it cleaned right up. You shouldn't have to glow the engine in summer or on every start (unlike some Kubotas) Did you clean the air cleaner?


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## haypoint (Oct 4, 2006)

Have we ruled out old fuel? There is a company in Texas that made an adapter that mates the Delco starter to the Belarus tractor. You should be able to locate it with a google search.


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## Rob30 (Nov 2, 2004)

I add a few liters of oil after every 9-10 hrs. The tractor does not blow blue smoke. It smokes (grey smoke) from the pcv tube running down the side of the engine. I have been told by many belarus owners it is common. I wondered why it is not directed into the air intake instead?
Plus I find the oil sometimes dribbles out the dip stick. This is why I originally thout of bad rings.
The air filters I blew out with an air hose, but they are reusable, I hate them. I am never sure they are clean.
I would check for voltage drop between the batteries, but I am no good with my ohm meter. Something I must work on.


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## Rob30 (Nov 2, 2004)

I took apart the primer pump on the 500 today. I am a little ticked the dealer tryed to sell me a new one for $68. All it needs is a new oring.


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## agmantoo (May 23, 2003)

Rob, is the tractor throwing some wet droplets of oil out the exhaust?


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## Rob30 (Nov 2, 2004)

The exhaust is normal after starting. The exhaust from the pcv does have oil init I believe. I don't see any when watching, but there is oil on the side on the block where the pcv exhaust runs.


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## rambler (Jan 20, 2004)

I'd look at a slow starter, bad battery, or bad glow plugs.

Could be worse, but those are the things I'd look to first.

--->Paul


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## Up North (Nov 29, 2005)

A can of ether is like any other tool in the farmer's tool box.
If used judiciously it can be an asset. If used indiscriminately it can be a liability. There are times when it is an appropriate aid in starting.


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## Rocky Fields (Jan 24, 2007)

Hey.

You need to give it a tune-up.

Check for water in oil...sometimes white smoke is steam...possible head gasket leak for example.

RF


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## Rob30 (Nov 2, 2004)

I don't have water in the oil. I suspect a fuel problem or starter system problem. I can't imagine it is anything more serious because I don't think I have any symptoms of somthing more serious. Other then the exhaust coming from the pcv, but I have been told it is common for belarus tractors. Starting is my only big issue.


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## agmantoo (May 23, 2003)

If you do not want to ether the engine yet you want to find out if it is starving for fuel put a small amount of gasoline in a spritzer bottle and start cranking and squirt some of the gas into the air intake and she if she will fire. I think you have an air leak. Since you repaired the primer pump have you tried to pump the primer until you get resistance on the pump lever and then have another person to crank the engine over while you still manually prime? You definitely need to try that.


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## Ross (May 9, 2002)

We use ether on the Fords occasionally with no problem but I really can't stress enough it will hurt your Belarus. Been there, done that. Can you disengage the hydraulics to see if it will crank faster?


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## DaleK (Sep 23, 2004)

Not sure if this helps at all but our JD 6400 does much the same thing, 6000 series are known for the fuel lines between the tank and the filter deteriorating and allowing air into the lines (without leaking fuel out). If it's been turned off for more than about 12 hours I have to turn the fuel pump on and bleed air out at the filter before it will start.


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## fordson major (Jul 12, 2003)

start at the beginning, good batteries full charge and good heavy cables. clean the battery disconnect with spray lube and lots of exercise, pull the starter and make sure it is 12 volt, some newer models used a 24 volt starter and some of them have found there way onto older models. clean up the starter, make sure it is working well. local shop was making the delco starter conversion for belarus, his rebuild worked very well so we never went with the delco. do not fault the dealer for trying too sell you a whole lift pump, often the bore is corrupt, haypoints description is accurate! study the Manuel!!!!! it brought lots of insight!!! until your starting system works well it is hard to diagnose other problems . we use engine oil in the diesel to help lube the injection pump and injectors, don't matter the brand or size of the diesel. how bad was the oil in the bottom of the air cleaner? often take the air cleaners off older equipment we buy and soak the cleaner in detergent and water to thoroughly flush any dirt out of the material. the hydraulic filter can plug up enough too bog the tractor down as well, cleanable for a reason! minus32 is not the time too be looking into things!


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## Rob30 (Nov 2, 2004)

The weather forcast changed again. Raining again today. So I will be going over the tractor again. I will start at the beginning. 
I find the starter is slow. Tractor starts easily when pull started with the truck. The fuel hoses look original. I also am wondering about dirty injectors. Because the fuel filter cap was covered in build up. Not sure how to clean them. I have heard some peoplew add a bit of ethenol gas to their diesel. Tried either before but the battery was already starting to discharge. Didn't work it sounded like the engine hesitated when being turned over. Won't try that again. 
I havn't put the primer back on yet (job interferes with the farm). But I will be trying it today. 
I disengaged the hydraulics and that does help with the turning over. 
Will try soaking the breather filter in detergent.


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## Rob30 (Nov 2, 2004)

Primed the pump with the rebuilt primer and found a couple leaks. Not to sure if I have them completely fixed but the tractor started much easier. Also found a short in the glow plug curcuit. I'll post a new thread for the next problem.


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## agmantoo (May 23, 2003)

As I told you early on that you could not have any leaks from the fuel tank to the injector pump. You need to fix all the leaks. A leak made visible from pump with the manual primer is a major leak in a diesel fuel line. The next time you go to start the machine see how fast once you get the manual primer pumped to where you have a lot of resistance you can get on the tractor and start with the starter. You do not want this pressure created by pumping with the primer to have a chance to bleed off.


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## Midgard (Jan 23, 2015)

My Mihadra emits a very large of white smoke and sputters above 1500-1700 rpm. It starts easily and will run all day at 1500 rpm. Fuel is good. Oil is fine. Air cleaner is clean. I just replaced the fuel filter. No change. The tractor is dealer serviced. This happened before and other than removing the air filter, etc. I couldn't find anything wrong with it. It then ran wonderfully for 3-4 months. Any suggestions would be appreciated. Thanks.

Ed


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## coolrunnin (Aug 28, 2010)

Midgard said:


> My Mihadra emits a very large of white smoke and sputters above 1500-1700 rpm. It starts easily and will run all day at 1500 rpm. Fuel is good. Oil is fine. Air cleaner is clean. I just replaced the fuel filter. No change. The tractor is dealer serviced. This happened before and other than removing the air filter, etc. I couldn't find anything wrong with it. It then ran wonderfully for 3-4 months. Any suggestions would be appreciated. Thanks.
> 
> Ed


Is it naturally aspirated or turbo charged? Also how old is the tractor?

My natural aspirated mm602 doesn't like the ultra low sulphur diesel and smoked and sputtered until I found a guy who could adjust the pump, and I started running a half quart of trans fluid to 20 gal. of deisel.


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## haypoint (Oct 4, 2006)

White smoke is often a sign of a lean fuel mix, not enough fuel. Easy solution would be to find the air leak in a fuel line. Far more difficult would be an injector pump replacement. If this tractor has a computer controlled fuel mixture, you could have a bad sensor, causing a reduced amount of fuel sent to the injectors.


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## Darren (May 10, 2002)

Up North said:


> A can of ether is like any other tool in the farmer's tool box.
> If used judiciously it can be an asset. If used indiscriminately it can be a liability. There are times when it is an appropriate aid in starting.


I'm with the never ether crowd. Use WD-40 or spray silicone instead.


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## TnAndy (Sep 15, 2005)

agmantoo said:


> Since the engine will start hot I feel the compression is good enough if you can get the tractor's air and fuel hot with the glow plugs and the crank speed.



I'd vote glow plugs as well. 

My first tractor was a Yanmar, and never used the glow plugs on it...started every time.

Next tractor was New Holland with some Japanese engine, and absolutely would not start cold unless you hit the glow plugs (separate position on the key switch).

Current tractor is a Yanmar, again, doesn't need the glow plugs...fires right up.

Have an excavator with Izuzu engine.....will not start cold without glow plugs.

So it seems manufacturer related as to whether you need to use them or not.


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## haypoint (Oct 4, 2006)

TnAndy said:


> I'd vote glow plugs as well.
> 
> My first tractor was a Yanmar, and never used the glow plugs on it...started every time.
> 
> ...


Great advice. If Agmantoo hasn't gotten his tractor started in the 8 years since he posted that, he may need more than glow plugs.


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## mustangglp (Jul 7, 2015)

Well hopefully he tells us if he every got it running in 8 year's


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## Darren (May 10, 2002)

Midgard said:


> My Mihadra emits a very large of white smoke and sputters above 1500-1700 rpm. It starts easily and will run all day at 1500 rpm. Fuel is good. Oil is fine. Air cleaner is clean. I just replaced the fuel filter. No change. The tractor is dealer serviced. This happened before and other than removing the air filter, etc. I couldn't find anything wrong with it. It then ran wonderfully for 3-4 months. Any suggestions would be appreciated. Thanks.
> 
> Ed


Did the issue exist before you changed the fuel filter the time before the latest change?


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## nosqrls (Jun 9, 2012)

Midgard said:


> My Mihadra emits a very large of white smoke and sputters above 1500-1700 rpm. It starts easily and will run all day at 1500 rpm. Fuel is good. Oil is fine. Air cleaner is clean. I just replaced the fuel filter. No change. The tractor is dealer serviced. This happened before and other than removing the air filter, etc. I couldn't find anything wrong with it. It then ran wonderfully for 3-4 months. Any suggestions would be appreciated. Thanks.
> 
> Ed


 If you have air leaking into the fuel system, it will be at the fuel pump or before it. or the strainer in the injection pump needs cleaning or replaced. It is a fine mesh screen in the inlet of the injection pump to catch debris from filter change.


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## Seth (Dec 3, 2012)

I have never, on any thread, seen so much bad advice.


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## haypoint (Oct 4, 2006)

Seth said:


> I have never, on any thread, seen so much bad advice.


The wonderful thing about the internet, if you can't help, at least you can kick dirt on those trying to help.:hammer:


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