L2501 little to no power?

I've had my L2501 since new, almost 3 years now, and about 70 hours on the meter. It was a pretty dry winter here, so it didn't get used much. a few days ago I hooked up the rear rotary cutter and headed out to mow today. I let the tractor idle up to temperature, and then I drove out to the pasture. When I throttled up to PTO speed (PTO not engaged yet) the motor sounded like it was missing on 1 cylinder and I got a lot of black soot out the exhaust. I idled it back down and drove to the garage to inspect.

Air filter is 90% clean, plenty of oil, no warning lights lit, no leaks or odd signs.

Fired the tractor back up, this time it ran fine. Drove to pasture, engaged PTO on the cutter and began mowing. The motor was running a little rough, but not too bad. However the available power was too low to drive in middle gear (hydraulic transmission). I switched to low gear, still not enough power to pull a mild hill. I disengaged the PTO, and the motor was barely running at this point. RPM's would not change with throttle. It's basically limping at 1200 RPM.

Where do I begin my inspections as to why the motor won't make any power? Would this kind of issue be covered under power train warranty? I've got a few months left on the factor power train warrant (36 months).

Dunbar said:

There are a lot more experienced folk on this forum than me but I will venture to suspect the fuel as the root of your problem. I would change the filter and if the tank is less than half full, top it off with new fuel. If full I would drain it out and put in new fuel.

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Ugh! I hope you are wrong. I literally just topped off the tank with fresh fuel, after running it down all winter long. The fuel filter has about 20 hours on it and looks clean and clear. I pulled it off and drained the bowl and reinstalled with no change.

But now that you mention it, the only thing that changed since the last time it ran good was the fresh load of fuel that I dumped in. So maybe you've hit the nail on the head

North Idaho Wolfman said:

Never store a diesel tractor for any length of time unless the tank is full, and treated with biocide.

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Thanks NIW. What does algae look like in the fuel? Can you see it in the filter bowl? My filter bowl looks crystal clear and the filter does not show any sings of color change.

Update:

Thinking I may have had a gummed up injector, I pulled the fuel filter bowl, drained it and re-filled it with Sea Foam. Re-installed and ran the motor for about a minute, and parked it.

2 hours later, went back out, fired it up and it ran fine. Cut some grass, no problem. Heavy load on the motor, no problem.

I don't get it. Did the Sea Foam clean a clog that was in a fuel line or in an injector?

Thanks again guys.

Assuming I have (had) some algae growth in there somewhere. Is the right next step adding a biocide to the fuel tank and then just letting it run? I assume the fuel filter will collect the junk that passes that way and I'd have to hope that everything down stream of the filter will just pass through the pump and injectors and out the exhaust.

marksjeep said:

I'm curious if you solved the problem? I have a one year old 2501, 90 hours on the clock. I've had multiple occasions where it begins to stumble, miss, smoke slightly, and lose power while under load. Local dealer inspected and can not find an issue. It very clearly stumbles and begins running very rough, as if missing a cylinder. Fuel filter is new, lines checked and appear to flow freely, tank flushed. Everything that came out of the tank was crystal clear. Fuel filter housing did not seem obstructed in any way.

I'm beyond frustrated. I love the compact form factor of the machine, but the lack of power is disappointing. Most of the work when this occurs is not PTO based. Grooming riding arena area with small disk or chain harrow, towing a hay trailer, dragging gravel grader through the driveway. All will be fine then the machine falls on it's face and starts stumbling. Back out of the HST, let it run with no load for a few seconds and it clears itself out. Apply a load to the engine again and it may be ok or it may begin to miss again.

I find it hard to believe this is an algae issue. I run it enough that there is never stale fuel. It was frustrating enough yesterday that it's getting an appointment back at the dealer.

Curious if you solved the problem, as it sounds pretty similar? I'll post up if I find a solution to mine.

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MarksJeep,
As I shared earlier, my first step was to drain the fuel filter bowl, fill it with seafoam, screw it back on, run the tractor for about a minute, while cycling the throttle from idle to full and back. Then I shut it down and parked it for about 2 hours before starting it back up and it ran fine at that point.

The next day I went back to mowing with the PTO powered bushhog. The tractor ran fine for about 15 minutes and then went back to feeling like it was running on 2 cylinders and puking black smoke from the exhaust.

So, I did the seafoam-fuel filter bowl trick again and parked the tractor while I went and got some POWER SERVICE CLEAN DIESEL https://powerservice.com/psp_product/clear-diesel-fuel-tank-cleaner/ and poured 8 ounces in the full fuel tank. I let that sit for about a day and went out and mowed today for an hour with no issue.

I'm not a diesel mechanic, but I am a pretty good garage mechanic, so I"ll share my theory with you on this: These motors are air/fuel pumps. They should not misfire, unless there is a fuel/air delivery problem. Since we have no turbo, there is little chance of an air issue, so that leaves fuel. My issue occurs at wide open throttle, and has both a misfire type of sound and vibration as well as black smoke. I suspect I've got a fuel injector that is sticking wide open and causing another injector to be starved for fuel. The WO injector is causing the black smoke and the starved injector is leading to the loss of power.

My theory on the solution is the SeaFoam at full strength can be used as an injector cleaner, which probably helps my issue. And the PowerService additive is a lubricant that had quieted my diesel engines in the past and will hopefully keep the injectors working correctly.

Time will tell. I'll report back is the problem persists.