Issues with Ditch Witch running rough

[Shane N]

I've been using a Ditch Witch trencher with front backhoe the last few weeks to dig up stumps and to knock poplar over. It worked great through the first 6-8 gallons of diesel. Once it got below 1/4 tank, it started to run really rough. It'd run ok at low throttle, but it wouldn't sustain a high throttle for long.

I tried changing out the fuel filter. There was some orange "sludge" in the cavities below where the fuel filter sits. I cleaned that out. It ran good for another 30-45 minutes after a new fuel filter plus another 6 gallons of diesel. Then it started doing the same thing.

I've taken the new filter off and there isn't any more additional sludge, and the fuel looks clear. I let it sit for a few days and went out again today. It ran good for 5-10 minutes, and then went back to being rough again.

I have never worked with a diesel before, and I don't really know where to start. Any suggestions?

 

[nate379]

What engine does it have?

 

[bioman]

sounds like the fuel pickup line has a hole in it inside the tank ! keep it full of fuel & it should run good until it gets to that level.

 

[MasterMech]

How many hours are on this thing? Any smoke? Knocking? If the injector nozzles are leaking, clogged or spray poorly then it will run poorly, especially when it gets up to temp.

 

[shmodaddy]

Ok if it were me id toss the new filter and start with another new filter....there may have been sediment or something in the bottom of the tank that stirred up when filling it while so low. Is there a drain valve for the tank? If so try to open that up and see if any crud comes out. Is the fuel tank above the injector pump? If so id check for unrestricted flow at the injector pump. If the tank is lower than the injector pump you may have lost prime. In that case you may need to pump up the manual fuel pump and "crack the injectors" meaning to loosen the fuel line slightly at the injectors while running and let any air out. You can try some diesel kleen added to the tank its an injector cleaner / lubricant. Diesel engines designed before 2010 were built with a "high" sulpher content in mind. Now emission laws mandate ultra low sulpher content adding wear to the injectors and pump . The diesel kleen helps combat that plus its also a cetane booster.




Sent from my rooted and eclipse running X2--thanks nitro-- if im posting on here I'm probably supposed to be working! I can't help im addicted to HEARTH.COM!

 

[Shane N]

What engine does it have?

Deutz. Not sure the exact model.

 

[Shane N]

sounds like the fuel pickup line has a hole in it inside the tank ! keep it full of fuel & it should run good until it gets to that level.

After I put in another 6 gallons, it ran decent for a little while before running rough. It was running rough around 2/3 of a tank this time rather than 1/4. So I'm thinking this isn't the case.

 

[Shane N]

How many hours are on this thing? Any smoke? Knocking? If the injector nozzles are leaking, clogged or spray poorly then it will run poorly, especially when it gets up to temp.

I think something like 1500 hours. It smokes a bit when running, but nothing super terrible. I don't think it is knocking any worse than any other diesel I've heard running.

Ok if it were me id toss the new filter and start with another new filter....there may have been sediment or something in the bottom of the tank that stirred up when filling it while so low. Is there a drain valve for the tank? If so try to open that up and see if any crud comes out. Is the fuel tank above the injector pump? If so id check for unrestricted flow at the injector pump. If the tank is lower than the injector pump you may have lost prime. In that case you may need to pump up the manual fuel pump and "crack the injectors" meaning to loosen the fuel line slightly at the injectors while running and let any air out. You can try some diesel kleen added to the tank its an injector cleaner / lubricant. Diesel engines designed before 2010 were built with a "high" sulpher content in mind. Now emission laws mandate ultra low sulpher content adding wear to the injectors and pump . The diesel kleen helps combat that plus its also a cetane booster.

I put on a new filter last night and it still ran like crap. The tank has two valves on the bottom for two different lines. I don't see a way to drain easily. I don't understand why there are two lines. One goes to the fuel pump and one goes to the top of the engine. Do they do return lines or something?

I used the prime level on the pump while the fuel filter was off and the fuel seemed to be clean, but I'm not sure how small of particles can mess it up. Is the injector pump different than the fuel pump?

 

[lukem]

Check the spark plugs

You either have air someone in the line or pump, or dirt in the line, or both. I'm thinking you lost prime, still have some air in there...and as the engine heats up the air expands and exacerbates the problem.

Or...hopefully not...you smoked an injector.

 

[Shane N]

Check the spark plugs

You either have air someone in the line or pump, or dirt in the line, or both. I'm thinking you lost prime, still have some air in there...and as the engine heats up the air expands and exacerbates the problem.

Or...hopefully not...you smoked an injector.

Like I said, I'm a complete diesel n00b. After replacing the filters, I used the primer lever on the fuel pump for a while, and then loosened one of the fuel line bolts on the side and continued to prime it until a steady stream of fuel came out with no bubbles. I didn't see any bleeder valve, but who knows what I'm even looking for

 

[greg13]

Deutz Diesels Are usually trouble free. I would change the filters & drain some off of the bottom of the tank. One thing that DOES go wrong with them (and from your description this is not your case) is a blown head gasket. When they blow they usually dump motor oil into the cylinder and it will smoke so bad that you latterly won't see the motor.

 

[Shane N]

Pretty sure we found the issue.

We went back out to the woods to work on it today. I started by priming and bleeding the fuel system. It would run ok and off. I took the cover off of the fuel pump and there was a ton of crud built up behind the screen. I cleaned that out hoping it was just a decade's worth of build up but it still ran terrible. We then decided to drain the fuel. We disconnected the fuel line from the pump and... nothing. We tried to pressurize the tank with compressed air and... nothing. We then disconnected the fuel line directly below the tank and... nothing.

So we ended up taking apart half the rear end to get the tank off. Dumping it out found the culprit. Lots and lots of crud in there. Black, sand-like texture. We kept dumping the diesel (sans crud at the bottom of the bucket) back in and swishing it around and dumping it out. We visibly got a good cup worth of junk out of it by doing that. We left a couple buckets of brown diesel out there to check in the morning to see how much is in those.

We brought the tank back and rinsed it out with gasoline and still more crud. Then we took off the fuel gauge from the bottom and I ran my finger along the bottom of the tank. Felt like sandpaper. So we took the pressure washer and sprayed as much of it as we could from the bottom and top. Lots more junk came out. Sat the tank in front of a kerosene heater to dry it out and then sat it on a heated floor for the night to help it dry out further.

Tomorrow we are going to put some diesel in and some diesel cleaning additive into it. Hopefully that'll get rid of the rest of it.

Thanks for all the help. BIG THANKS to schmodaddy for reaching out to me with his phone number. I took advantage of it a couple times and he was a huge help! I love this site.

 

[fishingpol]

Does the fuel cap have charcoal built in the cap to reduce odors? I worked with a guy who put a fuel cap on a hot muffler cage and melted it until the charcoal fell out. Just a thought.

 

[Shane N]

I ended up running the trencher a lot this weekend, which is why I haven't posted an update yet. Cleaning out the fuel tank completely fixed the issue. It now runs absolutely great. We put some diesel cleaner into the fuel as well to make sure the injectors were clean.

Thanks for all the help everyone!

 

[semipro]

I've found that the rust that accumulates in fuel tanks is black. The rough surface on the inside of the tank is evidence of rusting. The only way to keep tanks from rusting is to keep the water out. Keeping them full of clean fuel helps. For storage I'd recommend you drain the tank and put something in the tank to prevent rust, perhaps a desiccant.

There was a discussion here on how best to store generators to prevent tank rusting some time ago.

 

[greg13]

One trick that I found in a situation like your's is to stick a magnet to the bottom of the tank, most of the rust will be attracted to the magnet and stay out of the fuel flow.