posted August 22, 2006 19:18               

A couple of months ago I had topped my paddocks and near the end of job the tractor lost power and cut out. I left it for a few moments and got it running very weakly and managed to get back to home. I tried it the next day and it seemed fine and I finished off the small bit of paddock no problem. Today I did about twenty minutes work and the same thing happened and I just got back before it died.

I got it running again weakly and tehn it cut out and will not restart. It seems to me like fuel starvation but what I do not follow is that this only seems to happen after a period of work.

I would be grateful for some guidance on the sytematic approach I should take to find the fault.

Thanks in advance

DWD

posted August 22, 2006 20:29               

quote:

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Originally posted by dewaltdisney:
My Dexta is playing up and I am not sure where to start looking.

A couple of months ago I had topped my paddocks and near the end of job the tractor lost power and cut out. I left it for a few moments and got it running very weakly and managed to get back to home. I tried it the next day and it seemed fine and I finished off the small bit of paddock no problem. Today I did about twenty minutes work and the same thing happened and I just got back before it died.

I got it running again weakly and tehn it cut out and will not restart. It seems to me like fuel starvation but what I do not follow is that this only seems to happen after a period of work.

I would be grateful for some guidance on the sytematic approach I should take to find the fault.

Thanks in advance

DWD

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posted August 22, 2006 22:55               

Thanks very much for the prompt reply. Yes, that sounds like a very good diagnosis of the problem. I will have a go at that tomorrow as I have a spare fuel filter.

Thanks for your help and I will let you know how I get on

posted August 23, 2006 15:13               

I replaced the fuel filter which was black and there was a load of sludge at the bottom of the holder. I cleaned it all out put a new filter in and topped it up with clean diesel before tightening it back up. Bled out all the points and it burst into life after a few turns, running as sweet as a nut.

I worked for an hour and then it started to falter and died same as before. I towed it up to home but the heavens have just opened here and it is raining hard. Just had time to get a tarp over my baby.

I am thinking that with all the gunge present in the filter then it must be the fuel tap filter that is blocked. This looks really hard to do after reading the process.

I only have a tap, no primer, so is it a case of draining the tank by taking the fuel line off and then unscrewing the tap. Does the tank have to come off (which looks really difficult to me)

Any info appreciated

Many thanks

posted August 24, 2006 20:40               

If it is the fuel : clean the entire fuel system. Because if there is sludge in the filter, there is sludge between tank and that filter.
- Filter in the tank
- Line between tanktap and fuel lift pump.
- Liftpump !
- Line between fuel lift pump and filter

To remove the tap from the tank, the tank has to be empty ! Only if you are very quick, you could unscrew the tap, clean it and have it replaced before the tank is empty

Is the fuel lift pump working ok ? This has to pump the diesel through the filter and a fault is no good thing.

Rgds
Jos

posted August 24, 2006 21:52               

PS Black filter is a indication of a water problem and Diesel bactera and microbes. Especily if it is spoiiy looking

quote:

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Originally posted by dewaltdisney:
Arrrgh.....

I replaced the fuel filter which was black and there was a load of sludge at the bottom of the holder. I cleaned it all out put a new filter in and topped it up with clean diesel before tightening it back up. Bled out all the points and it burst into life after a few turns, running as sweet as a nut.

I worked for an hour and then it started to falter and died same as before. I towed it up to home but the heavens have just opened here and it is raining hard. Just had time to get a tarp over my baby.

I am thinking that with all the gunge present in the filter then it must be the fuel tap filter that is blocked. This looks really hard to do after reading the process.

I only have a tap, no primer, so is it a case of draining the tank by taking the fuel line off and then unscrewing the tap. Does the tank have to come off (which looks really difficult to me)

Any info appreciated

Many thanks

DWD

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posted August 26, 2006 00:48               

I did not know about the microbes that can live in the fuel and I reckon that this must be the problem. The tank is venting okay and it is clean metal on the interior of the tank. The remaining fuel looks black though and the sludge in the filter case and the black fuel I found when I cleaned it the other day would indicate that this microbes are the problem.

Can someone give me a name of a fuel additive I can buy to keep the tank clean after I have purged the tank and fuel lines please?

Thanks again

posted August 26, 2006 02:24               

For those that are not familiar with Fuel Microbes here is a little article from yhe net.

" "
The bacterial colonies can be seen floating in diesel collected in bottle

Bacterial contamination occurs when some strain of bacteria get carried forward from the refining stage. The rest enter by exposing the fuel to the atmosphere in storage tanks, delivery trucks, wagons, dispensing stations, pipelines and in vehicle's own tank. Some of these bacteria are aerobic, which require oxygen for multiplication and the other are anaerobic which live in oxygen-depleted atmosphere like sulfate reducing bacteria
Biodegradation of Diesel.
Invisible to naked eye, the bacteria spores are actively mobile in the fuel. The fast reproduction and multiplication time allows them to exploit any good growth conditions provided by the temperature, agitation and water contents in the fuel. Bacteria rely on the fuel (carbon) molecules and the molecules of additives present in the fuel to support its life cycle.

The great diversity of bacteria's life cycle means that it can utilise any organic substance in the fuel. As bacteria keep on with its life cycle of consuming fuel molecules and secretion, partial breakdown of products occur. These secretions of breakdown fuel become food for other microbes. This continuous process assisted by fresh supply of diesel into the tank, leads to the rapid development of a consortium of microbes which biodegrade the fuel.

The extra-cellular slime produced by the bacteria help them to attach to the surfaces and also protect the colony from changes in the environment. Slime (bacteria colony consisting of different interdependent organisms ) may deactivate or prevent the effectiveness of chemical biocide widely used for controlling bacterial activity.

Proliferation of aerobic bacteria and the formation of bio film as discussed above help to promote the growth of sulfate reducing bacteria in the fuel. SRB are highly dangerous and known for causing corrosion in fuel tank, pumps and injectors. In addition to this, SRB produce hydrogen sulfide, a harmful and lethal substance. A concentration of 300 ppm in the air we breathe is considered life threatening. Storage tanks are highly susceptible to SRB attack.

Contamination and degradation affects engine components adversely. The sludge and slime block filters to cause restriction of diesel flow, promote corrosion and pitting in fuel pump and injectors to cause uneven and unregulated fuel supply and large biomass forced through the filters can cause incomplete combustion.

The emulsifying agents produced by bacteria help moisture to get emulsified with diesel and gets injected into the cylinders to cause corrosion in pistons and piston rings. All these factors contribute to filter blocking, lack of power, fuel pump and injector malfunction, increased smoke, engine noise and vibration.

Less efficient and degraded diesel cannot produce the required power from each combustion stroke from the injected volume. This will result in more fuel volume to be injected resulting in increased fuel consumption.

The diesel filter is an important component in a precisely balanced fuel system. Any malfunction in the fuel filter affects the engine performance adversely. Biomass and slime produced by bacteria block the fine filter elements in a very short time causing fuel starvation.

quote:

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Originally posted by dewaltdisney:
Thanks for the replies all.

I did not know about the microbes that can live in the fuel and I reckon that this must be the problem. The tank is venting okay and it is clean metal on the interior of the tank. The remaining fuel looks black though and the sludge in the filter case and the black fuel I found when I cleaned it the other day would indicate that this microbes are the problem.

Can someone give me a name of a fuel additive I can buy to keep the tank clean after I have purged the tank and fuel lines please?

Thanks again

DWD

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posted August 26, 2006 11:34               

Is there a water draw off point on the Dexta, I cannot seem to find one?

Your suggestion of putting lead shot in the tank sounds good but would a bar of lead be better as there is less chance of the fuel tap gauze getting blocked by the pellets? Also with a short bar I could leave a nice loop formed so it could be easily fished out if necessary. Any views?

Once again thanks for all the advice

DWD

posted August 26, 2006 13:50               

quote:

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Originally posted by dewaltdisney:
Tmac, thanks for that information, it is quite amazing that an organism can develop in such a harsh environment. I am convinced that this is the problem now but I will have to get a couple of new filters before I proceed with clean up.

Is there a water draw off point on the Dexta, I cannot seem to find one?

Your suggestion of putting lead shot in the tank sounds good but would a bar of lead be better as there is less chance of the fuel tap gauze getting blocked by the pellets? Also with a short bar I could leave a nice loop formed so it could be easily fished out if necessary. Any views?

Once again thanks for all the advice

DWD

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posted August 27, 2006 11:41               

Okay, a lot for me to think around but I have a few ideas going on now. I will come back and let you know how I get on.

Thanks once again for taking the time to explain things,

posted September 01, 2006 17:54               

I will go through this so that any inexperienced owners (like me) might find this thread useful in the future.

Armed with two new filters I firstly checked the newly fitted fuel filter to see if that was blocked but it was clean as when I put it in last week. This pointed me to the fuel tank filter and I was faced with taking the tap out which was stretching my mechanical confidence a bit.

So, mindful of the wet feet warning, I syphoned off the remaining fuel in the tank into two plastic containers so that I could see any obvious contamination but it looked okay. I will check them after they have settled in a few days to see. I then used a smaller tube to syphon out the sump at the bottom of the tank and this had a few black blobs and it was watery but not microbe nation as I was expecting I was surprised to see that the fuel tap entry is on a shelf set above this sump in the tank, presumably the sump allows water and stuff to settle there. (Pity there is not a bleed point here)

I then detached the fuel lines and blew them through and the lift pump with compressed air. There was nothing in the tissue I placed to catch any debris blown out.

So next it had to be the fuel tap removal so I looked and saw that by removing the side plate below the tank it allowed the tap to be unscrewed easily. The filter was totally clogged with black bits so I cleaned it thorougly and reassemebled.

Filled up with new diesel and bled through (dab hand at this now) and as soon as the fuel was up it fired up on a few turns.

So it seems that it must have been a clogged fuel tap filter and only time will tell now if it is fixed or not. I left it running for twenty minutes and did a short run around the field and it seemed fine so......watch this space.

Thanks for the help once again.

posted September 12, 2006 18:37               

There does not appear to be a bleed point in the Dexta tank and as I found the fuel tapb outlet is above the level of the sump area at the bottom of the tank. The best way to check is to put a piece of clear plastic tube in to this sump area and syphon out the bottom. As water is heavier than the fuel oil you can clear most of any water gathered there in this way which will reduce the possibility of the microbes having an environment to breed.(I think)

I think my problem was just dirty fuel that had blocked the gauze inner tank filter as it has been running fine since.

I keep my tank topped right up now so hopefully there is no room for condensation to form. I also am filtering the fuel in a funnel now.

I think my next job might be to replace the fuel pump diaphragm as it has developed the classic hunting when I start up. Still thinking about this though

posted September 13, 2006 12:16               

This is the way most of us (at least I have)have gone through to understand her "strange behaviours".

May this be the reason why a Dexta is a "SHE" ?

Jos

posted September 13, 2006 20:47               

I actually refer to my Dexta as a 'he' and I called him Ted after the cricketer Ted Dexter. Strangely my whole family and friends now ask affectionately after him and a friend sent him a birthday card for a laugh. My dad, who is 84 now, always asks me 'How is Ted' as soon as we speak

posted September 14, 2006 14:01               

What might be worse was if Ted went with a Fergy and we got a mixed race offspring. What would it be..... a Dexergy....this has wandered into fantasy now

posted September 14, 2006 16:52               

quote:

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Originally posted by dewaltdisney:

What might be worse was if Ted went with a Fergy and we got a mixed race offspring. What would it be..... a Dexergy....this has wandered into fantasy now

DWD

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