Engine races - intermittently - whilst on tickover or lows revs

[treaney]

Zetor bretheren,

My Crystal 8011 exhibits an annoying and potentially dangerous (for the engine) problem. Like all "juicy" problems it is intermittent and unpredictable.

Once the engine has heated up (it has never happened yet from cold), with the tractor stationary and engine on tickover or slightly reved and moving e.g doing yard scraper work, it will suddenly increase engine speed to full revs in the matter of a couple of seconds.....and before you say it - No! it's not me accidentally pressing the foot or hand throttle!

The engine continues to race until I move the hand throttle to the off position. Putting a load on the engine also cures the problem.

I'd appreciate the advice of anyone who might have experienced a similar problem and found the cure.

Over 2 U!

Tom

 

[Renze]

I think i know that problem: But it's different.

My dad had an old Volvo 740 turbo diesel, with the very poor designed Volkswagen 2.4 Diesel, known from the LT van.
Anyway to make it run better in the cold, my brother adjusted the fuel pump for some extra sgtationary revs.

somehow, after a few minutes i saw my brother running back to the car, it was running to the red line at full revs. That engine used to wolk on only 4 or 5 feet instead of 6. when it started to run better, a few seconds later it became a little upset and slowly began to howl.

This was caused by a too high stationary fuel gift.
I dont know if this is the same on your 8011, because the Motorpal inline pump has not really a stationary device (you shut it off by putting the hand throttle to stop, not by turning the ignition key back as on the Bosch rotating VE pump.

I think the rev adjustment has trouble, i think the flyweights are stuck. If they function properly, they adjust fuel gift back to normal if it's at the revs.

The flyweights are in the bowl on the cab's side of the fuel pump. Maybe you should refresh the oil (and wash it out with gasoline or diesel before putting new oil in) or maybe a spring is broken.

hope this helps.

 

[markku]

Hello!

Does the injection pump has own oil ? Or is it the newer model what is connected to engine oil pump? If it is the older version change the oil of injection pump If the oil is dirty, it has wrong viscosity or oil level is not right the pump can do what ever it want to.......

 

[Renze]

Yes, these pumps have their own oil bath. I cannot remember where the fill and drain plugs are.

 

[woodbeef]

Might also want to check and make sure you are not getting air in the fuel system somewhere......

 

[treaney]

Woodbeef,

Sounds logical but how do I check that my Crstal is not "sucking" air on the fuel lines?

Tom.

 

[markku]

Renze,

I started to think, what is unnormal69)

I have sended a picture for you about year ago, There was a picture of the cold starting button. In the same picture number 6 is filling and level plug of the injection pump. And 18 and 7 are drain plugs.

 

[treaney]

Markku,

My tractor is a 1977 Zetor Crystal 8011 with the Motorpal pump. I'll check/change the oil in it at the weekend.

Does anyone know what viscosity/SAE rating oil this needs?

Tom

 

[woodbeef]

Hey Tom,

Check the complete fuel system,not just the lines. Look for leaks,splits,and bulges,etc.....Also make sure the fuel cap is tight and not leaking.

 

[treaney]

Hi Guys,

No luck yet with what you have suggested but something else that I have observed in using the tractor is that:

1. It takes a long time (seconds) for the engine to die after you cut off the fuel supply and

2. That there is very poor engine braking when descending a hill - engine tends to increase in speed.

Do these point to anything else being wrong?

Tom

 

[markku]

How many engine hours it has?

And how much do you fill the engine oil between services (200 hours?

And what about cold starting? Does it start well even it is cold weather?

There might be one solution, but it comes only if the engine is used a lots of hours. About over 15 000 hours.

 

[Renze]

Hmm... It likes the revs.... 80F1 ???

I think i have to think about it, before saying anything...???

 

[crystalman]

Sounds like it could be the governor weights and or linkage connecting the weights to the fuel rack giving problems(inside the rear casing of the fuel pump) If you can find a good injection specialist it may be possible to repair the pump fairly cheaply if you can catch it before it goes wrong big time. Years ago we had a similar thing happen to our old T20 TVO when it was idling.Had to find a second hand set of weights on their carrier and a new timing chain after it exploded!

 

[treaney]

Renze, Crystalman, Markku and Woodbeef:

Woodbeef - I've elimnated sucking air.

Markku - I re-built the engine (but not the pump) in 2000. It has done less than 1000 hours since the rebuild. Cold starting is a doddle...first time, every time even in the not so artic minus -5 degree C frost we get in Ireland.

I changed the oil in the injection pump yesterday. About 10cc of diesel like consistency oil came out but it took 200cc of multigrade 20W/50 to refill it! It is a better testament to Zetor engineering than to my preventative maintenance schedule[/].

I've got my fingers crossed that no damage has been done internally to the governer/weights mechanism by the low oil level. I'll keep tabs on it to see how it behaves...

Happy Zetoring for 2004!

Tom

 

[Renze]

My guess is also that something might be wrong with the centrifugal weights... remove the big cap on the back end of the pump and check if the flyweights can move freely.. (they should be spring tensed, i think so you have to overcome the spring tension whem you test it..

I have never done anything to a fuel pump, both the 4712 and 6718 we had, werent touched but acquired their magnificent levels of performance the natural way...

 

[treaney]

Hi Folks,

My Zetor 8011 is no longer a 8011 Formula 1!

I took the advice of contributors to the forum - it was a problem with the governer! I removed the injection pump and brought it to a specialist where I got the governer fixed. There was a slider with a lot of wear. This was replaced. After putting it on the machine, everything else checked out.

I am happy now because I have engine braking downhill and the engine throtlles back quickly.

BTW to get the governor seen to cost me E60 once I knew what the problem was. Talking to injection specialists before this, they gave quotes of several hundred Euro to re-condition it. So it's a case of knowing what your taking about, definitely pays off. I have you guys to thank for that.

Igor quoted me a price of E320 for a new pump which is the route I would have taken if this hadn't worked. I'd prefer to go that route than spend a couple of hundred Euro reconditioning.

Tom in Ireland

 

[Renze]

Well, congratulations...

At a contractor my brother works, they had a 130 hp SAME Antares for some years, the Fendt importer also became SAME importer so they had one for try.
It wasn't really old, maybe 3 to 5 years, but the governor seized and the engine ran over it's revs till the conncecting rods slammed through the sidewall of the block..


By the way, How many hours does that 8011 have done ?

 

[Tom in Ireland]

Renze,

My Zetor 8011 had an engine rebuild in 2000. The clock isn't working but she will has done less than 1000 since the re-build BUT what about before the rebuild?

I don't know but as she was maintained OK - appears to be normal wear and tear for a tractor heading for 30 years old. In Ireland, in the 1970's, Zetor Crystals cut ALL of the silage in the country. They were much better than the MF' and DB's and other tractor's of that time so my tractor had a pretty tough working life befire going into "retirement".

I reckon that she had 15,000 to 20,000 hours in her working life from 1977 to 1990. From 1990, she was used with a power front loader for silage bales.

I had her working today in my yard backing filling a trench with my 2m hydraulic box. Working a treat.

Tom.