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6711 started smoking - SOLVED!

G

grumpy6711

Member
Level 1
Joined
Jul 4, 2010
Messages
88
Location
England
First name
grumpy
Machinery:
Zetor 6711
me again
my trusty 6711 seems to have taking up smoking
Is there anything i can check for or eliminate from the equation without any special tools?
orcould it be terminal
Its always smoked a little if you looked for it but the other day whilst raking it started to smoke in not a good way.

I think that its un-burnt diesel as opposed to engine oil, as it sounds like its over fuelling (stuttering)
the base of the U-bend on the exhaust has a lovely black oily discharge and is smoking well too.

since i bought it a few years ago it has never revved cleanly above 'working' speed, stuttering as if over fuelling when attempting road speeds. I always assumed that this was pump related (and therefore expensive) but cos it ran perfectly well at lower revs did not worry about it. I see on another post ...
about adjusting a pump for more fuel. i was wondering where one adjusts this in case the previous owner has had a go and its running 'rich'.
it has a motorpal setup pics here...

Dropbox - File Deleted - Simplify your life

www.dropbox.com

all suggestions and ideas welcome
 
Hi,
Watt collor smoke, if blakk: unburnt diesel like cloged up airfilter or opend pump, coldstart stuck on. If blue: oil like stuck pistonrigs, vorn valvguides, ore wear in general. Stutering at high revs is most likly govenor that nedes an oil change/refill.
Bjarne
 
smoke colour between dark grey and black i think.
so far...
checked cold start button - clicks in and out as it always has, so i dont think its that?
i have removed air filter and run engine - still the same. loads of suck at the fillter - probably suck in any passing wildlife!

 
Bugger!

Dark grey smoke is hard to diagnose as it is a combination of Black, and either blue or[/] white.

Black = over fueling (some under full load or accelleration is ok)
White = unburnt diesel vapour (dirty injectors or pump timing, or even low compression)
Blue = Engine oil (stuck or worn out oil controll rings)

Under light load conditions the black should dissapear leaving just blue or white to diagnose the problem.

Is it puffing (just 1 cyl smoking) or continous smoke, all Cyl's effected?
 
Bugger!
....
Is it puffing (just 1 cyl smoking) or continous smoke, all Cyl's effected?
Click to expand...

I'd say continuous- and worst when you grab a handful of throttle from tickover, goes from light puff, puff, puff, puff (technical term ) to big cloud of smoke and then smoke lessens as it reaches the revs. if that makes sense - so it smokes worst whilst engine accelerates quickly.
The strange thing is it was fine all week, then the next day i started it - smoke galore! which makes me suspect its possibly something sticking or broken as opposed general wear.?
may get a chance to have a tinker tomorrow, weather permitting.
 
Were you working it hard last week? or just putting about?
Could be stuck oil rings........ 3-piece oil rings never break, they can gum up or the expanders can collapse, either from old age or overheating (i had this happen on a 1974 Skoda 110R......... it used 4L of oil to get to work and back.......... a round trip of less than 20km), ......
the old style cast iron oil rings can break or gum up,.... not sure what Zetor used but i would expect 3 piece on a 7 series UR1.

Keep an eye on the oil level, if it is smoking that bad the level will go down over 8hrs use......... if the level goes up..... then it is over fuelling and Diesel is running down the bore past the rings into the sump...... you will also see a slight drop in hot oil pressure as the diesel thins the oil.

if it is "puffing" smoke at idle it could be just 1 CYL effected. test by cracking the injector pipes loose one at a time.
if there is oil coming out the exhaust U vent check if it smells like oil or diesel ...... Rub some between your finger and thumb .... and take a big sniff
also oil will be more slippery than diesel (finger rub test)

It will either get better or worse with hard work

 
Grumpy, make sure the cold start button housing hasn't worked loose and screwed outward. This is where the max fuel is adjusted, from memory, out is more. It has a locknut that locks against the pump housing. It may have unwound while you where working, but you would notice the button would be in a different position.
One other thought, try running it without the muffler, the baffles can either collapse or block up, causing excessive back pressure.
 
update:
smoke i have now decided is white, with possibly a hint of black when you grab a fistful of throttle.
after reading an earlier post i flushed the governor through with diesel cleared out the rusty brown watery stuff and refilled.
is this correct?... Three orifices on the guvna, top - fill, bottom - drain , middle - fill level? so theres only about an inch of oil?
hasnt made much difference but im sure it wont hurt it.
 

checked! not loose, but can be turned thru 360 degrees and positioned at any angle. I think its supposed to be like that???
 

just poodling about -- only got 5 acres and half of that yet to be reclaimed from nature!

oil level steady and still golden (almost) from the oil change i did two years ago!

attempted to crack injectors but afraid of shearing pipe, so giving it a soak of penetrating oil see if its any easier tomorrow.

finger rub test of 'exhaust' oil - black and slippery and definitely smells like diesel.

we're due two more days of sunshine so will be buck-raking tomorrow or the day after and we will see what a bit of work does to it!>

fingers crossed
 

Grumpy, I don't think it's supposed to be like that. The bit the actual button is in, shouldn't be able to rotate from memory, it should be locked with the locknut. I have the later style pump with no button, but I will check my dad's 6045 on the weekend to refresh my memory.


 
Sometimes the hexagonal top end will move apart from the threaded bush it is supposed to be pressed onto...

See of the threaded bush also turns, and if the locknut turns...
 
checked! not loose, but can be turned thru 360 degrees and positioned at any angle. I think its supposed to be like that

--------------------------------------------------------------------------------
On my 6745 the Hex with the cold start button can be rotated about 270 Deg ....... (indpendently of the threaded bush and locknut)........ but not 360Deg
 
locknut tightened a bit (but less than a quarter turn) and now cannot move cold start button by hand as i could before.
Tis possibly a little a better. pushed some wet hay around the field for an hour, smoked when started but settled down after five minutes and wasn't overly noticeable whilst working. Still smokes under acceleration though so further investigation still required.
cheers guys
nev
 
Sounds like you need to wind in (i think in?) the cold start button a little to re set the position of the max fuel stop, .......... you dont know how many turns it wound it's self out whilst loose.
test at 1 turn at a time and lock the locknut before testing........................................

or bolt up a turbo to get enough air to burn all the excess diesel and gain another 40hp
 
Well things have changed! for better or worse remains to be seen???
i managed to remove the cold start button (just) but the lock nut would not move, i couldnt hold the rotating barrel bit without possibly damaging the threads. so gave it all a good clean and put it back on.
now theres me thinking if i can wriggle it out past the compressor i can wriggle it back in. Wrong , in the end i had to slacken the three nuts mounting the pump so i could move it back about 2mm to get the csb back in.
During the loosening i did discover that the awkward nut at the back of the pump was not tight! i undid it with a finger!!
So now all back together and whilst it still smokes under acceleration, the oily exhaust discharge has stopped and it revs a little more steadily and smoothly. max revs is now probably around 2000rpm where as before i'm sure it was more like 3000.
test drive tomorrow!
cheers again
nev
 
I would assume that if the locknut is frozen onto the threaded barrel, then it has not moved from where it should be
So when you tightened the locknut you did effectively screw the barrel back in to the correct position....... assuming it was correct before it came loose
Some black smoke under acceleration is ok......... blotting out the sun is not

 
coldstart stuck on. If blue: oil like stuck pistonrigs, vorn valvguides, ore wear in general. Stutering at high revs is most likly govenor that nedes an oil change/refill.
Bjarne
 
Yay,........ a new kind of spammer, just re quotes random text (complete with origanol spelling mistakes) from the same thread and trys do sell us DVD's ...... and they are not even about Tractors!.........................

What,.......... did you think we would not notice?
piss off knoddy your type arn't welcome around here.
find another site to peddle your dubbed dvd's
 
AHA!!
After fixing the brakes last week decided to do a spot of verge and hedge trimming. After 100m of verge it was getting a bit smoky in the cab so stopped to investigate.
All the smoke was coming from the exhaust u bend and there was a lovely coating of oil all over the block just behind it. On further inspection 'oil' was also seeping from exhaust manifold on cylinder 1 (nearest cab).
So it would seem that the smoking issue is with just the one cylinder.
I pulled the rocker cover off to see if it was anything obvious (it would have to be obvious cos i've never been under a rocker cover in me life!)
couldnt see anything out of place but recalled a recent post about a bent pushrod. pulled off the rocker and Hey Presto! one bent rod!
straightened it in a vice/ hammer > and problem gone.
NO MORE SMOKE

I'm sure a tappet adjust all round will probably help a little further but at least thats one problem solved.

Happy days!
 
I'm sure a tappet adjust all round will probably help a little further but at least thats one problem solved.
Click to expand...
I think too little valve clearance is the reason that your pushrod bent in the first place... Then the compression shuts the valve, even though the rocker cant go further.

It can burn your valves, doing hard work with not enough valve clearance (when hot exhaust gas is leaking past)


 
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