engine ran backwards "I think"

dodgejack · Dec 16, 2004

engine ran backwards \"I think\"

I was winching some trees with my Kubota & Farmi today when the trees hooked behind a stump I kept on pulling trying to break them free. Well I just about killed the tractor. I let go of the rope on the engine's last gasp. Well the engine kept running but rough and the PTO quit. I jumped inside thinking I broke something, switched the PTO out and back in, nothing, getting real worried now. Looked down oil pressure light on OH NO!! Black smoke coming out the front by the air intake. I shut it down. Nerviously fired it back up everything works fine. Could it have been running backwards? and if it was would the exaust come out the intake? I've had chainsaws run backwards before I'm pretty sure the exaust came out the exaust. Answers Please!! /forums/images/graemlins/confused.gif

DK35vince · Dec 16, 2004

Re: engine ran backwards \"I think\"

( Could it have been running backwards? and if it was would the exaust come out the intake? )

The answer is yes its possible.
I had the same thing happen in tri-axle dumps before.
Almost stalled it, caught it with the clutch at the last second
Twice with a Detriot 2 stroke diesel. I knew what had happened when the black smoke was coming out of the air filter box /forums/images/graemlins/grin.gif
I know a 3406/3 and a quarter Cat can also run backwards because I did it once /forums/images/graemlins/shocked.gif
Just shut them down and restart and all was well !!

tillerkiller · Dec 16, 2004

Re: engine ran backwards \"I think\"

I have seen it happen with two-stroke diesels. Check your air filter to make sure that it is all still there. Don't know if you hurt it, but the concrete truck that did it did not get hurt by it and it was obvious that this was not the first time that it had happened to it either! /forums/images/graemlins/tongue.gif

Charlie_in_TX · Dec 17, 2004

Re: engine ran backwards \"I think\"

It is not possible for a 4 stroke to run backward unless it is a direct injection. If it is caburated or if there is a precombustion chamber it will not run backwards. If it is a type that will run backwards it would do so very poorly as you discribed and it would be pushing exhaust out the intake. Shouldn't do any long term damage.

For those who have had it happen on a 2stroke (diesel or gas), the intake and exhaust still operate properly, right? Just the timing is off and the shaft spins backwards.

briggs_man · Dec 17, 2004

Re: engine ran backwards \"I think\"

( It is not possible for a 4 stroke to run backward unless it is a direct injection. If it is caburated or if there is a precombustion chamber it will not run backwards. If it is a type that will run backwards it would do so very poorly as you discribed and it would be pushing exhaust out the intake. Shouldn't do any long term damage.

For those who have had it happen on a 2stroke (diesel or gas), the intake and exhaust still operate properly, right? Just the timing is off and the shaft spins backwards.
)

Yea Right tell that to all the Cats, Mack's, BSD,Perkins, Cummin,s Detroit , That they wont run backwards . The sam heck they wont it dont make a diffrence to the injector pump how that Injector is set up to inject into the cylinder , Cummins and 2 stroke detroits , if the pump can deliver fuel to the Injectors and the rocker arm can move they will run backwards . Carburated diesel???????? Oh boy .. Yes they will run back wards and they do . 2 stroke 4 stroke it dont matter if it aint got a computer controled fuel syestem and it gets a backwards thrust on the crank they will run.. My 6.2 Detroit in my pickup will kick backwards now and then , they sound about the same either direction its 4 stroke and Indirect injection

caburated or if there is a precombustion chamber it will not run backwards Ill sit right here and bet you 1,000 Bucks thats wrong ill go out in my old VW Rabbit drift it down the drive way and catch it in reverse going forward with the key on and leave er sit their and run backwards

_RaT_ · Dec 17, 2004

Re: engine ran backwards \"I think\"

I have had it happen several times to me on a NH 2120. The first time I thought uh oh, what did I do. The second time I knew exactly waht happened. It was easy to do to the NH 2120 as it has a large loader and bucket for the size of the engine. It was failrly easy to almost stall only to have it just catch itself and end up in the backwards rotation. Folks here have also mentioned their JD 4710 has run backwards.

briggs_man · Dec 17, 2004

Re: engine ran backwards \"I think\"

If i can catch our 79 2600 Diesel ford just right with the shut off i can kock it backwards and it will run till i kill it, course about 10 secs is all ill safley give it do to low or no oil pressure.

JerryG · Dec 17, 2004

Re: engine ran backwards \"I think\"

My past tractor a MF 1250 (Iseki) was indirect injection and it ran backward on me once.

8561 · Dec 17, 2004

Re: engine ran backwards \"I think\"

Not really applicable to this particular situation, but I thought I'd point out that some engines will do it by design. I own both a 2004 and a 2005 Ski Doo. To go into reverse on both sleds, you hit the reverse button on the handle bar at idle, it slows the engine by retarding the timing and kills it for a split second. The motor re-fires on it's own (they are both pull start only) and spins backwards, which in turn spins the track backwards. Both are two strokes, one with semi-direct injection, the other with carbs.

RockyMtDan · Dec 18, 2004

Re: engine ran backwards \"I think\"

I'v had customers drive there tractors forword in a revers gear to a phone to call me. It sure can happen with all most any eng. I dont believe a hst tractor would drive at all or even be susseptable to start backwords.No worries mate.

Soundguy · Dec 18, 2004

Re: engine ran backwards \"I think\"

( if the pump can deliver fuel to the Injectors )

We had an old 60's era Cat D6-9U dozer where I work.. it very frequently ran backwards and would shower oil out the air bath filter into the operator platform.

Our old mechanic also mention about some diesels and fuel.. Says he's seen some old diesels especially detroits that 'ran away' and when he threw a choke plate on them, the sucked in a seal, and then started syphoning oil for fuel.. had to lug the engine down to kill it. That must have been quite an experience.

Soundguy

GregMVT · Dec 18, 2004

Re: engine ran backwards \"I think\"

My brother is rebuilding a 36' wood cabin cruiser with twin 327CI engines, mid 1960's model. He says one is for forward, the other for reverse and that one runs backward.

LeRoi · Dec 18, 2004

Re: engine ran backwards \"I think\"

Twin engines in boats are usually made with one running CCW rotation & one running CW rotation. The engine that runs clockwise has a different camshaft and distributor drive gear in the engine and a different gearbox and propellor.
The counter rotation keeps you from having to fight to keep the boat going straight. It wants to torque steer to the right (I think).
I don't believe it's possible for a carburated gasoline engine to run backwards without modification, because if it's exhausting through the intake, it cannot get fuel to operate.
Leroy

RickB · Dec 18, 2004

Re: engine ran backwards \"I think\"

Won't cause any long term damage except that caused by no lube oil pressure or flow. Running without oil pressure usuallly causes long term damage, unless you are real fast at doing major overhauls; then it is only short term damage.

dodgejack · Dec 18, 2004

Re: engine ran backwards \"I think\"

Thanks for the replies. I took the air cleaners off, the inside one was somewhat sooty so I changed it. DO you think the motor was hurt it ran about a minute with low or no oil pressure? Thanks again

RickB · Dec 19, 2004

Re: engine ran backwards \"I think\"

I wouldn't think so. My point was that running an engine backwards was not necessarily a harmless event.

Bobm · Dec 19, 2004

Re: engine ran backwards \"I think\"

Jack - i've had the identical running backwards phenomenon, and with the same circumstance. I suppose it doesn't matter how one goes about invoking a diesel to run backwards - if everythings at operating temp and the thing is spun in the opposite direction, off it goes. This has happened to me several times when really hammering on my Farmi, drawing the tractor too close to stall, and then quickly releasing the clutch on the winch. Its never happened with other applications like chipping wood and drawing the the engine slowly down - I'm certain that stall point, and then complete freedom to spin backwards has to be just right. At any rate, no damage has been done, and within my circle of diesel pals, no damage has ever occured if the engine was shut down in reasonably short order after the reversing.

dodgejack · Dec 21, 2004

Re: engine ran backwards \"I think\"

Thanks BobM for the informative response. I have a question about engine speed. I run around 1700 rpm-- 400 pto thinking better to bog down through the rough spots or hangups than to snap something. What rpm do you run when winching? Thank you

rockyridgefarm · Dec 21, 2004

Re: engine ran backwards \"I think\"

Sure has been an informative read - I never would have guessed any of this!

Charlie_in_TX · Dec 21, 2004

Re: engine ran backwards \"I think\"

( ( It is not possible for a 4 stroke to run backward unless it is a direct injection. If it is caburated or if there is a precombustion chamber it will not run backwards. If it is a type that will run backwards it would do so very poorly as you discribed and it would be pushing exhaust out the intake. Shouldn't do any long term damage.

For those who have had it happen on a 2stroke (diesel or gas), the intake and exhaust still operate properly, right? Just the timing is off and the shaft spins backwards.
)

Yea Right tell that to all the Cats, Mack's, BSD,Perkins, Cummin,s Detroit , That they wont run backwards . The sam heck they wont it dont make a diffrence to the injector pump how that Injector is set up to inject into the cylinder , Cummins and 2 stroke detroits , if the pump can deliver fuel to the Injectors and the rocker arm can move they will run backwards . Carburated diesel???????? Oh boy .. Yes they will run back wards and they do . 2 stroke 4 stroke it dont matter if it aint got a computer controled fuel syestem and it gets a backwards thrust on the crank they will run.. My 6.2 Detroit in my pickup will kick backwards now and then , they sound about the same either direction its 4 stroke and Indirect injection

caburated or if there is a precombustion chamber it will not run backwards Ill sit right here and bet you 1,000 Bucks thats wrong ill go out in my old VW Rabbit drift it down the drive way and catch it in reverse going forward with the key on and leave er sit their and run backwards )
Well, I guess I need to study up on the precombustion chamber and other inderect injection methods. The point that I was trying, and failed, to get across was fuel must be injected (or otherwise) into the cylinder, not the intake as is done in fuel injected and carbed gas motors. I didn't say carbed diesel, I added carbed to include gas motors into the discusion.