Loud Knock + Dark Smoke Start & Stop While Running

[kh99]

Hi all,
1601 was running fine:

• Changed oil & filter about 20 hrs ago. Changed brands of both, but no change in oil light behavior at start up.
• Oil pressure light would go out as normal before full start up (after about 4 seconds of cranking).
• Oil color still good (fairly clear) and oil level is right at the top line.
• Would start right up & restart with no problem.
• Not running hot & water level good.

I took a couple minutes yesterday to get off tractor and pick up some rocks.
While it was just sitting / idling (after a couple hours light work):

• It all of the sudden developed a loud knock and dark smoke.
• Died before I could move it.
• This happened like flipping a switch = symptoms did NOT occur gradually.
• Was able to restart, but did this a couple more times as I was moving it back near tools.

Got it moved back, but afraid to run it.
Witnessed a Cat Dozer do something similar a couple months ago, but no one there knew why.

Any help greatly appreciated.

 

[chopped]

Just a guess. How about the fuel filter or air filter?

 

[winston1]

Does the knock sound like a rod or main bearing knock? Are you saying the knock comes and goes?

 

[MJPetersen]

I would say injector. The injector that does not close properly will dribble fuel--hence loud knock (preignition) and excess fuel (black smoke). I would therefore guess that you have an injector that is sticking. Some additive that would give a bit more lubrication would probably help.

If other things in the area are doing this too (Cat Dozer) then maybe your fuel is ultra ultra low sulfur and lackin gin the lubrication needed for older engines designed for normal fuel at the time.

Mike

 

[normde2001]

All you can do is to eliminate fuel and air, (in and out), as a problem, then go inside and have a look, ( pull pan and/or head).

 

[kh99]

Thanks for the quick & GREAT replies!!

>>Just a guess. How about the fuel filter or air filter?
How many hours are these fuel filters usually good for?
Could a bad fuel filter cause it to come on all of the sudden like that?

>> Does the knock sound like a rod or main bearing knock?
Knock as in compression knock, and loud as in that momentary knock when first cold start.
>>Are you saying the knock comes and goes?
It started full loud, and then seemed to fade in and out as I drove the 200 ft to its parking spot.

>>maybe your fuel is ultra ultra low sulfur and lackin gin the lubrication needed for older engines...
I did notice that the fuel I was buying lately did not have the same obvious green tint as before. Is this green tint the sulfur content?

So maybe a little Automatic Transmission Fluid?
How much per five gallons should be about right?

Thanks

 

[Tvern13]

I would use some Power Service, Seafoam or Marval Mystery Oil to see if that would clear it up.

 

[MJPetersen]

I like Marvel Mystery Oil If I can find it, otherwise some ATF would work. Try a 1/2 - 1 cup in 5 gallons. Buy fuel from some other place too.

Mike

 

[bruce1966us]

sounds like a fuel problem to me. Don't go yanking the engine apart until you diagnois the problem.

 

[YanmarFever]

Disconnect 1 injector line at a time by loosening it, and see if the sound goes away or gets worse.
That will also tell you which injector is bad, IF that's the problem.

Also shine a light into the fuel filter to see if its dirty, if it is, change it with a napa #3262

Like Norm said, don't tear into the engine yet !