Engine knocking

[Jim L.]

That's a lot of water taken out.

I would get some diesel containers and tubing. One end of the tubing to the bottom of the tractor fuel tank, start flow to container by syphon. Continue to hold tubing to bottom of tractor fuel tank to suction all water from bottom of tank. Remove all fuel, look with flashlight to verify since it is on a slope.

Do whatever filter work needs to be done. Reload tractor with fresh fuel.

 

[Cheryl]

Not to state the obvious but .... water is somehow getting into your fuel. Did you empty the tank completely when you installed the new filter? Four ounces of water just doesn't appear.

No, I didn't drain it completely. I just drained quart. In hindsight, that's what I should have done. But it should still start now I've drained the water out of the new separator, no? Even if it's only for a minute?

 

[Jim L.]

Just too much water in that tank.

Fuel pumps use the diesel as a lubricant and coolant. Water provides the means for oxidation of precision metal parts. The long-term concern is ruining the fuel system.

Short-term is getting that contaminated fuel out so it will start. Apparently it is overwhelming the separator, and the water/diesel mix doesn't have enough energy to fire off under compression.

 

[aaluck]

No, I didn't drain it completely. I just drained quart. In hindsight, that's what I should have done. But it should still start now I've drained the water out of the new separator, no? Even if it's only for a minute?

As stated by @Jim L. it may be contaminating it immediately. Drain it completely flush it with diesel start from scratch.

FILL IT FROM A DIFFERENT SOURCE THAN THE FUEL IN THERE NOW.

 

[torch]

I've mentioned this before in other threads, but I use a product called the Water Worm mini. It is a desiccant in a sock, miniature version of the ones for storage tanks. Soaks up all water (from condensation, etc.) before it accumulates into a pool and causes problems. When it is full, simply hang to dry and reuse.

 

[Cheryl]

Thanks for all the assistance folks. I did manage to drain all the fuel and water, replaced the fuel filter... again, and got it started. Maybe it's just my imagination, but it doesn't sound the same. The normal familiar diesel knock seems washed out by other noise. It's hard to describe... it won't come through on audio.

 

[rbargeron]

A very small amount of water in the fuel can cause an ominous rap in diesel engines. Need to be very thorough in getting rid of every bit of water - including taking the tank & separator out and cleaning everything. Then find and elliminate the source - contaminated fuel storage, transfer cans, cracked fuel tank cap, gaskets.

Water sinks to the bottom of the tank and doesn't mix in much until the fuel level is low - then the sloshing can mix some water into the pickup line - it only takes a few drops getting into the diesel pump to sound like the engine is coming apart. In the cylinder, the water flash boils from the heat of compression causing a more violent diesel ignition than normal. It sounds terrible - but usually doesn't do actual damage - except to the operator's nerves

 

[aaluck]

Thanks for all the assistance folks. I did manage to drain all the fuel and water, replaced the fuel filter... again, and got it started. Maybe it's just my imagination, but it doesn't sound the same. The normal familiar diesel knock seems washed out by other noise. It's hard to describe... it won't come through on audio.

Is it running now? Did it eliminate it stalling?

 

[Cheryl]

It sounds terrible - but usually doesn't do actual damage - except to the operator's nerves

That it did!

 

[Cheryl]

Is it running now? Did it eliminate it stalling?

Yes, I only ran it about 15 minutes with the mower, but it ran ok. I'll be doing some more mowing today. I'm not expecting any problems. I'm going to check the separator before running every time now.

 

[dvcochran]

New to the forum and new to country living. I bought an older M5030 last year and have loved the tractor. I don't know much about diesel engines but I know enough to shut it down when it starts knocking. Today I started to do a little mowing. After warming up I set off cutting about 100 yards when it suddenly started a knock. I pulled back the throttle and the knock went away. But add a little fuel and the knocking starts again. I shut it down immediately. I'm suspecting water in the fuel is possible? I did see a puff of smoke that looked like it was coming between the manifold and muffler. Can't tell you the color of if it was always there.

I have some mechanical ability, but I just don't know enough about diesels to feel confident I won't make something worse. I would really appreciate some advice.

I have an older M4700 that is notorious for 'knocking' if the hydraulic controls are in the wrong position. It will sound just like an engine knock.

 

[RCW]

A very small amount of water in the fuel can cause an ominous rap in diesel engines.

It sounds terrible - but usually doesn't do actual damage - except to the operator's nerves

Dick - - -Is this what they call injector knock, or is that something with the injector itself going bad? Or both?

It's a little sway from Cheryl's thread, but I think pretty closely related....

 

[JerryMT]

Just got the tractor pulled back to the barn. I never noticed that the fuel filter had a drain on the bottom. Opened that up and it was full of brown oily water. I collected probably a third of a cup... maybe more of water. Before I start it back up, is there anything else I should do? If it were gas, I'd start it and try burning off the water left in the line. Diesel, it seems that's a big no-no.

If you had that much water in the bottom of the filter would advise you to drain all the fuel out of the tank via the line ahead of the filter. Drain it into a container and let it sit and you can decant the good fuel off. It is possible that you have bacterial sludge in your fuel tank which is cause by bacteria that live in the fuel water interface. look for sludge in the drained fuel. You tank outlet may have a strainer in it and if you can remove that do so and look for debris and sludge on the strainer. Flush a gallon or two of the clean decanted fuel you removed from the tank and see if more crud comes out of the tank. repeat until there is no more crud coming out. Replace the filter and reconnect the strainer and the tank fuel line and bleed per the manufacturers instructions. Fill the tank with fresh fuel and continue and check for an un-impeded fuel flow to the injector pump. (You may have a lift pump between the filter and the tank or the filter and the IP. They sometimes have a cover with a screen under it. If you have one of these , remove the cover and clean the screen.)When you have that follow the rest of the bleeding instructions and try a start.

Water can get in the fuel in many ways. Contaminated fuel, condensation, leaving the cap off the fuel tank and having rain water get in, etc. Those are management issues that you can control. Keep the tank as full as possible will minimize condensation, Buy fuel from places that move a lot of diesel and store it properly. Treat it with additives that make the water bead up on the filter and drop down into the drain bowl. You might use some biocide also if you found bacterial sludge in your tank.

Clean fuel, blended for ambient temperatures in your area, is a basic requirement for diesel engines.

Hope this helps you.

 

[GeoHorn]

I can appreciate the desire to save a little money and “decant” the water out of the diesel….. but that’s a False Economy, IMO. Diesel (and a lot of similar fuels) can hold water in suspension as a normal matter. The amount of time and temperature will determine whether or not and how much water will be absorbed/held by the fuel….and at what temperature it will coalesce out and create a problem..

Cut to the chase: Get rid of the old fuel. Use only new, clean, dry fuel to resolve this issue.

 

[Cheryl]

I can appreciate the desire to save a little money and “decant” the water out of the diesel….. but that’s a False Economy, IMO. Diesel (and a lot of similar fuels) can hold water in suspension as a normal matter. The amount of time and temperature will determine whether or not and how much water will be absorbed/held by the fuel….and at what temperature it will coalesce out and create a problem..

Cut to the chase: Get rid of the old fuel. Use only new, clean, dry fuel to resolve this issue.

I'm saving it for my diesel shop heater

 

[JerryMT]

I can appreciate the desire to save a little money and “decant” the water out of the diesel….. but that’s a False Economy, IMO. Diesel (and a lot of similar fuels) can hold water in suspension as a normal matter. The amount of time and temperature will determine whether or not and how much water will be absorbed/held by the fuel….and at what temperature it will coalesce out and create a problem..

Cut to the chase: Get rid of the old fuel. Use only new, clean, dry fuel to resolve this issue.

I wasn't suggesting that she use the decanted fuel in the tractor. I was suggesting she flush the tank with the decanted fuel. I guess i should have specifically stated that it should not be used in the tractor. She apparently figured it out since she says she wlll use it in her shop heater.
Sorry for any confusion.

 

[Joisey]

A very small amount of water in the fuel can cause an ominous rap in diesel engines. Need to be very thorough in getting rid of every bit of water - including taking the tank & separator out and cleaning everything. Then find and elliminate the source - contaminated fuel storage, transfer cans, cracked fuel tank cap, gaskets.

Water sinks to the bottom of the tank and doesn't mix in much until the fuel level is low - then the sloshing can mix some water into the pickup line - it only takes a few drops getting into the diesel pump to sound like the engine is coming apart. In the cylinder, the water flash boils from the heat of compression causing a more violent diesel ignition than normal. It sounds terrible - but usually doesn't do actual damage - except to the operator's nerves

I know this is an old post. Water causes such an extreme knock when introduced to a diesel cylinder because it expands 300 times when it turns to steam. That I learned when I trained for my black seal high pressure steam license. Now when I look online, the claim seems to be that water expands 1700 times in volume when it turns to steam. Must be new math water these days.

 

[Joisey]

I've mentioned this before in other threads, but I use a product called the Water Worm mini. It is a desiccant in a sock, miniature version of the ones for storage tanks. Soaks up all water (from condensation, etc.) before it accumulates into a pool and causes problems. When it is full, simply hang to dry and reuse.

Thank you for that tip. I ordered one for my storage tank

 

[Chanceywd]

I know this is an old post. Water causes such an extreme knock when introduced to a diesel cylinder because it expands 300 times when it turns to steam. That I learned when I trained for my black seal high pressure steam license. Now when I look online, the claim seems to be that water expands 1700 times in volume when it turns to steam. Must be new math water these days.

40 years ago in my volunteer fireman training they used the 1700 water to steam number in explaining properly applied water to a fire.

Bill

 

[Joisey]

40 years ago in my volunteer fireman training they used the 1700 water to steam number in explaining properly applied water to a fire.

Bill

Well then, my number is another thing I can chalk up to a bad memory. Been 40 years since I went to class.