4400 running backwards

[simonmeridew]

It happened twice over the new years weekend: I was winching out a large white pine with my L4400 and Farmi winch, when the log caught in the snow, slowed then briefly stalled the engine, then I quickly released the winch cord and the motor had started again, but this time running backwards. I immediately ran to the key and shut it off. How do I know it was running backwards: the first time I didn't, the second time I did: the tach showed no RPMs and the oil light on the dash was lit.
I figure that I stalled the motor, and there was a potential energy stored up in the winch cable and caught log, which wanted to pull the winch cable back out, and when the motor stopped and the cable pulled back out the motor started running backwards. No idea how much power it had, I shut it off within a couple seconds, but it was idling very smoothly. Sounded normal.
simonmeridew

 

[dfkrug]

Wow, that could cause real damage to your motor. I imagine that both
your engine oil pump and implement pump would cavitate almost
immediately. And, as you saw, no oil to the bearings.

 

[krackerjack9]

Im not sure if that is possible?? I would think the injection EMC would not let this happen. Unless the existing fuel pressure is the only thing that was still sending fuel thur the injectors, It may not have ran very long like this. But I find it hard to believe that could happen, though from what you describe that would be very good circumstance that in theroy would cause this to happen.

 

[mrwitty_1]

I have seen this happen before on 2 stroke diesel engine but not on 4 stroke. May be we will learn how this happened. I'm interested.

 

[DK35vince]

I have seen this happen before on 2 stroke diesel engine but not on 4 stroke. May be we will learn how this happened. I'm interested.

I have had it happen to me with both a 2 stroke and a 4 stroke diesel engines in the past.
A 2 stroke Detroit ( several times) but also a Cat 4 stoke.
Can't explain why they can run backwards. I just know I've seen it happen.

 

[driver444]

Ya know, I've actually seen this happen more than once. The last time I saw it happen was on an old Mack dump truck with a 237 HP Mack engine. The guy was backing down into a ravine. I'm not sure what he did with the clutch, or what gear he was in, but it sounded awful, and black soot poured from the air cleaner.

 

[ccsial]

Im not sure if that is possible?? I would think the injection EMC would not let this happen. Unless the existing fuel pressure is the only thing that was still sending fuel thur the injectors, It may not have ran very long like this. But I find it hard to believe that could happen, though from what you describe that would be very good circumstance that in theroy would cause this to happen.

The L4400 does not have an engine computer that controls the injection. It is all mechanical and will run backwards.

 

[john_bud]

As they say on the Bud-Light commercials, "Dude!"

Are you running the 'bota at PTO speeds or are you running light on rpm's? It shouldn't stall out if running at 540 rpm. Also, adjust your slip clutch if it has one. It may be rusted froze - happens all the time. If it only has a shear bolt, get a slip clutch.

Ever watch NASCAR? when they spin and go backwards the engines are forced backwards and they blow every time. Bearings don't like the no-oil diet. They (racers) can afford it as the engines are cheap disposable deals, but our tractors are expensive! (joke! hold your fire NASCAR fans, I know what they cost.)


To be clear on you issue. When it bogged, did you release the winch and the engine fired right up from an "off" state? Can you reach back and depress the tractor clutch by hand, then release the winch? That may stop the problem. Still, I think a correctly operating slip clutch would be the right solution.


Whoa! Had a brain dealie - you know, a thought. Isn't there supposed to be an overrunning clutch in the PTO to keep just this from occuring? (There is). You may have an issue in the 'bota that needs attention. If that ORC is froze and transmitting torque from the PTO to the engine, it will transfer torque from a rotary cutter also. When that happens the tractor keeps moving forward no matter what you do. Talk to some grey beards that drove tractors with non-live PTO's. A lot of barns, trees and ditches were run into over the years.

 

[pdowling1]

I also suspect your slip clutch isn't doing it's job. No way you should be able to stall your engine like that, unless you're operating at idle speeds. If you are, rev it up some before you destroy that baby by running it backwards. Running backwards is VERY bad. You can't see where you're going!

 

[ccsial]

I'm not certain of this but I think the older tractors that had the PTO and transmission tied together needed an ORC. When the clutch was depressed the PTO was still connected to the Transmission (if it was engaged) and the energy in the implement could move the tractor.

The L4400 has an independent PTO so it is not tied to the transmission. There is probably not an ORC since the PTO is tied directly to the engine. I suspect that the incidents of running backwards is quite unusual and Kubota didn't take this winching scenario into account.

Some skidding winches have slip clutches to prevent stalling. Check to see if yours has one. It may be frozen or need adjusting.

Adding an external ORC would solve the running reverse problem too. It would not prevent stalling though.