Slobbering

Super-H-Mike · Mar 16, 2012

Ok, Some diesel fuel questions on the board today, so here is mine. I have been seeing the term "slobbering" come up occasionally. I assume this is reffering to overfueling at low speed and loads? Is this characteristic of older IH diesels only ? I have only seen it talked about with larger engines, true? I have only owned one diesel tractor in my life so far, an 1800 Oliver with a Wakashau motor. It never did this, it would idle smoothly all day if you wanted it to. Just trying to learn something today, thanks !

Janicholson · Mar 16, 2012

Carbon from ideling for short times coats the exhaust system with soot. Because the system is basically cold, moisture condenses in the passages as well. The moisture collects the soot and makes a paste. This is then expelled out the pipe. Long modest use results in heated pipes and no slobber. Hard use = no slobber.
Repeated short start and stop operation Massive slobber. Some combustion chamber design mre some less carbon coating. Jim

Rootsy · Mar 16, 2012

Really a term you'll hear used in reference to 2 cycle Detroit Diesel engines where due to water leaking past liner seals in engines such as the 92 series or in all series where oil leaks past the blower seals, rings or wrist pin seals and into the air boxes. The oil / water, etc, is expelled out the air box drain tubes and drips on the ground... hence the word slobbering. Generally the sign of mechanical issues or an engine in need of over haul.

Bob M · Mar 16, 2012

Like Jim says it's soot, unburned fuel and condensation from incomplete combustion. This nasty gunk then leaks out around exhaust system joints and down the outside of exhaust stacks.

Most any diesel will slobber when operated with little or no low load and with coolant temp below normal. Some diesels tend to slobber more than others - my experience has been 2 stroke Detroits, also early diesels from IHC, Minneapolis-Moline, Case, etc. are the most notorious.

Incidentally Alco (4 stroke) and EMD (2 stroke) locomotive diesels also slobber if left idling very long. Then when suddenly loaded they throw up massive quantities of smoke and sometimes even angry orange flames until the slobber gets burned off. It's most impressive!

Super-H-Mike · Mar 16, 2012

Thanks for the info guys. My Dad farmed for years with an 886, and I ran it a bunch too, but I never recall it doing anything like this. Maybe the older models were more likely to ?

wisbaker · Mar 16, 2012

Diesels like to be worked, taking them out and getting them hot and working them hard is the best tune up you can do. I guess they're like people and need their cardio exercise. The old phrase "carbon on the valves" does apply to diesels, especially the old Detroits. Put your foot in the pump and don't back off and it'll outlive you!

Allan in NE · Mar 16, 2012

"Slobbering" is nothing but unburnt diesel fuel.

All diesels do it.

Allan

Slobbering

Super-H-Mike

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Janicholson

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Rootsy

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Bob M

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Super-H-Mike

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wisbaker

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Allan in NE

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