What's a good engine idle speed for a small Yanmar "80" diesel engine?

[mslisaj]

I like the slower RPM as long as it stays smooth. Can't afford to rattle out my teeth at this point in my life. As far as the EPA, well they are too deep in our business already. Besides this tractor of mine may sit for a week at a time, burns practically no fuel but I'm sure Yanmar had to prove it to someone on emissions to sell it. The engine has a coolant thermostat in it to keep the engine warm so I'm not worrying about that either. What's really curious is in all the material I have on this engine and tractor there is no discussion about what the idle speed should be set to.

 

[thepumpguysc]

BECAUSE of the wide field of application of these engines, the rated speed will vary considerably.. along w/ the idle speed.
I DO have the book that covers a lot of engines & applications..
Basically they're lumped into 2 categories.. CL> constant speed & VM> Variable speed..
The CL is set and I quote> 1200 rpms or more..
The VM is set and I quote> 800 rpms or more.. w/ an asterisk on the 4TNV106[t] which is set 1100 rpms or more..
IF you think yours is to hi.. turn it down to where you want it.. it doesn't void ANY warranty & the screw if left unsealed FOR A REASON>> SO IT CAN BE ADJUSTED..

 

[Supraman0614]

The engine itself may run fine at 900 rpm, but the hydraulic pump, alternator, water pump, etc might not be rated to operate at that low rpm. I have a 3-cyl Shibaura on my NH front mower that will run at 800-900 rpm, but the battery light comes on because the alternator is turing too slow to power the electronics. It isn't hurting anything to leave it where it is though. LS designed it that way for a reason.

 

[buickanddeere]

1350rpm will not blow up the engine, wear it out or burn excess fuel.

 

[LS Tractor Owner]

While operating the unit today, I noticed my rpm was at 1250 at idle. Definately smooth, but right on the brink of starting to vibrate/rattle things. When moving, I bump up the rpm to about 17-1800. Using the hoe or the loader, up to at least 2500 if it's light or easy work. Digging deep or really filling the loader, I run at 3000 rpm.

 

[mslisaj]

While operating the unit today, I noticed my rpm was at 1250 at idle. Definately smooth, but right on the brink of starting to vibrate/rattle things. When moving, I bump up the rpm to about 17-1800. Using the hoe or the loader, up to at least 2500 if it's light or easy work. Digging deep or really filling the loader, I run at 3000 rpm.

That's exactly how I do it. It's kind of interesting as through the night these last days it's been down to the 20's in the shop. The little engine kicks right off running but complains about it with about an 800 rpm sputter and idle. Then it sorts itself out and runs nice at the 1330 or so. I just love the way this little diesel runs but it's like me, doesn't like the cold.

 

[rider7767]

My FEL has almost no lift power at 1350. I usually have it running at least 1800 if I am moving the tractor around. It is has a much faster drive speed at a higher RPM. You say it will operate the attachments at 1350 but that is far below the PTO speed. The BH is much quicker when running higher than idle.

I just went an looked at the manual. Page 3-8 section (9) Throttle lever states, "Notice: Set the engine speed over 1500 rev/min for stability of hydraulic system while driving or working."

I checked mine today. It is set at 1280 RPM. This tractor is not affected by tier 4 being under the 25hp threshold (24.5). I would guess they match the engine speed with the minimum RPM needed to move the tractor at idle. I would think it would stall the engine like dumping the clutch if it was to low. My thoughts. That and $2 will get you a Coke!

 

[WCarp]

What are you trying to achieve with the idle? 1350 rpm doesn't seem to high to me. I seen on the forum, someone with the NH Boomer 24 said their tractor was set to idle around 1500 rpm. The NH is the same as the xj2025 with the s3l2 engine made by Mitsubishi but I would think NH set the idle around 1500 because 1000-1300 rpm is pretty rough on these tractors. And like tomplum said, xj2025 owners have been running their tractors higher then the set idle. These small engines are used in more than just tractors and are set to idle at all different speeds, my brother in-law has a generator with a 3 cyl Kubota engine, the thing will run continually at 2000 RPM day after day...

I have also read on the forum, people with the Shibaura engine saying how smooth it runs but not sure what the idle is set at. I'm sure LS set the idle at 1350 rpm on the Yanmar 80 for a reason...

Just thought I would mention that the low idle RPM for my NH Boomer 3050 (2013 with CVT) which has a Shibaura engine is 1,050. Since I'm used to older tractors, I thought the low idle was rather high but apparently, with the newer ones, it's normal.

 

[Username Taken]

Crankcase dilution - Wikipedia

It is more common in situations where fuel is injected at a very high pressure, such as in a direct-injected diesel engine.

When a mixture of air and fuel enters the cylinder of an engine, it is entirely possible for condensation of fuel to occur on the cooler parts of the cylinders. The condensate may wash the lubricating oil from the cylinder walls, travel past the piston rings and collect in the oil pan, thus increasing wear and also diluting the lubricating oil. Since the less volatile components of the fuel will have the greatest tendency to condense, the degree of crankcase-oil dilution is directly related to the end volatility temperatures of the mixture.

Wet Stacking Causes, Effects and Solutions from CK Power

WHAT CAUSES WET STACKING?
Like all internal combustion engines, to operate at maximum efficiency, a diesel engine has to have exactly the right air-to-fuel ratio and be able to sustain its designed operational temperature for a complete burn of fuel. When a diesel engine is operated on light loads, it will not attain its correct operating temperature.

When the diesel engine runs below its designed operating temperature for extended periods, unburned fuel is exhausted and noticed as wetness in the exhaust system, hence the phrase “wet stacking.”

 

[Gary Fowler]

All the diesel engines I have had experience with idled at around 900 RPM or a bit higher. Any lower than about 800 and you get a really rough engine idle.