Diesel newbie-operating questions

[deserteagle71]

Can you please say more about this? I've heard similar things but never understood why. I have a pretty new tier 4 with about 60 hours on it, and still haven't gone through a re-gen cycle. It works hard some times, but usually it has a light load. And I'm also unclear whether by "idle" most people are referring generally to running the engine without a load, or more specifically doing that at low rpm. I think I've heard people use the word both ways.

What does your owner's manual say? The manual for my Kubota specifically states, in no uncertain terms, to keep idling at a minimum. That means keeping the rpms up so the exhaust stays hot.

Screen shot from my owner's manual:

(PM = particulate matter)

 

[CobyRupert]

…what if you idle it unnecessarily, but then make sure to work it hard and hot for an extended period of time at the end of the day? Or every few days. Or often…often enough. It has to partially mimic a regen cycle.

 

[SmallChange]

What does your owner's manual say?

Mine does not say much about this. It does say that when driving the tractor the "throttle lever" should be set for an engine speed above 1500 (though it's not a throttle). And it lists various RPMs such as min, max, and nominal in the table showing driving speeds for different gears. There's no reference to "idle" in the index and text searching only turned up the things I mentioned, and no advice on running the engine without a load. Also no mention on setting engine speed when the tractor is sitting still but working through the PTO or hydraulics (other than notes about what engine speed correlates to 540 RPM PTO speed).

Thanks! The explanation about exhaust temperature does make sense!

 

[PILOON]

With all the gearing in a tractor I don't hesitate to drive my tractor immediately after start up, even on cold winter days.
OK, I do so at idle speeds and I do have it plugged in so the oil is warm and flowing.
Sort of just put putting along and naturally not working it. When I slip the clutch there is no change in RPM's at all.
OK, not idling but for sure loafing.

 

[Midniteoyl]

When just doing general non-PTO duties, loader work, driving around, etc, I run my idle up to ~1500 rpm and use the linked pedal. About 3.5 months with no regen yet.

 

[RalphVa]

Recently I bought my first diesel engine. This 40 year old engine came complete with a 40 year old Yanmar YM2310 tractor wrapped around the engine.
The manual says to pull the throttle handle all the way to full throttle, pull the decompression knob out and crank the engine until it starts. Once it starts set throttle to 1500 RPM or lower and let it run for at least 3 minutes before using the tractor. When stopping the engine it should be run at an idle for 1 minute to cool off before shutting down.
I have questions now about how to run this engine. I live just north of Seattle so the temperatures the engine will experience will be pretty moderate most of the time. Is it really necessary to run the engine for 3 minutes to warm it up? if so then why? And do I really need to idle the engine for 1 minute to cool it down? It's not that hot here usually and when we do have weather above 90 degrees I'm not gonna be running the tractor anyway.
I see folks who let their diesel engines idle away for long periods of time on a pretty regular basis. Not just big trucks but pickup trucks, backhoes, excavators, and small engined equipment like my tractor. I shut off my gasoline engined Case 580 CK backhoe rather than let it idle for more than a few minutes. Is it a bad thing to shut off my diesel, shovel stuff into the loader, and then restart it after maybe 5 minutes to do more work? And to do this several times a day?
For the next couple days I will be using a rock rake on an area I will be planting with grass. After a few passes with the rake I sort out and shovel all the rocks into the loader and then dump all the rocks into a hole I dug with my 580CK for this purpose. It takes 5 to 10 minutes to do this shoveling and sorting. I don't like having to let the diesel idle while I sort and shovel. So that's why the above question is asked.
I guess my last question for now is about fuel. I use the diesel fuel that comes from the pump right next to the gasoline pump at my local gas station. It's the same fuel that over the road vehicles use. I know it is low sulfur fuel and that 40 years ago engines were designed to use different fuels. On top of that, my engine was designed to be used in Asian countries, not the USA, and maybe their diesel was significantly different than the fuel available to me today. Because of this I am using a diesel fuel additive that is supposed to clean injectors and increase the cetane rating. Should I continue to do this?
Thanks,
Eric

Drove diesel cars for 38 years. Never ever just let them sit and idle after starting. Just started and drove close to normal. Just didn't rev to maximum for about a mile. On the Benzes, you had to rev to maximum to get anywhere.

On the tractors for 17 years, just start and run gently for a few minutes. Diesels won't warm up much just sitting.

Very seldom used an additive. Did after one Benz was stored for 4 years, and diesel had turned brown. It won't do that now with ULSD. Diesel sits in 60 gallon tank for the generator for much longer.

P.S. Had one diesel car for 25 years and 215k. It was the one that got stored those 4 years.

 

[Tx Jim]

Very seldom used an additive. Did after one Benz was stored for 4 years, and diesel had turned brown. It won't do that now with ULSD. Diesel sits in 60 gallon tank for the generator for much longer.

Storage life of ULSD is dependent on if fuel has any biodiesel in it. Biodiesel doesn't store very well for extended periods of time

 

[DieselBound]

[Pertaining to the question of idle time] Allowing the hydraulic fluid to warm up a bit is, IMO, more important that trying to warm up the engine.

I pretty much go by the look of the exhaust. Initially you're going to see visible particles*, but then that clears up, and at that point the engine oil is likely flowing well enough to begin to operate the tractor. I always have to travel a bit of distance before I'm actually engaging in work, so the travel is at 1,500 to 1,800 rpm and then I'll crank it up as needed.

* Note that even with a DPF you'll see signs. Might be moisture? At any rate, it's still a gauge that I use/go by.

 

[Bentrim]

Just a few thoughts of someone that has worked with farm machinery for over 20 years, small engines for over 15 years. Also studied recommendations of people that should know how to operate engines, manufacturers, and other "experts".

Most recommend to start engine allow a minimum time to run at about half throttle, 30 seconds to a minute, the go to work s l o w l y. Reason-- the engine will warm up faster doing work than sitting idle, wear is reduced as the engine warms up faster, fuel is burned more efficiently by a warmed up engine, pollution is reduced. On diesels recommend starting at WOT then pulling the throttle back as soon as it "hits" before the rpm starts to climb. This usually gives a full fuel load for quicker starting, some pumps has an excess fuel button for the same purpose.

If an engine especially a diesel is left to sit idling the combustion chambers cool down and fuel is not burnt efficiently or completely. You will get what is called wet stacking on most diesels that are not worked hard. Wet stacking is when unburned fuel collects in the exhaust system and runs out of the manifold, muffler, or exhaust connections, most folks will say "oil is leaking where the muffler connects to the manifold" nope not oil but diesel fuel that has turned black from soot. After an diesel has been warmed up and started it is usually not difficult or hard on the starter to restart, of course there are some that need glow plugged even in 90* weather. Shutting the down save wear on the whole tractor and reduces pollution.

As for shutting down the engine IF the tractor has been loaded do NOT shut off immediately leave it idle to half throttle for a few minutes before shutting down. Years ago some farmers had a problem cracking heads, found they would be plowing, or other heavy loads and just shut it off. Give the engine temperatures time to equalize and get rid of the hot spots before stopping the engine, then bring down to an idle for a minute before shutting down, especially the turbo needs the heat equalized and removed from the exhaust side or the seals coke with oil and leak thru the exhaust. Ever hear a turbo whirring after engine shut down? remember no oil no lubrication.

Even had some farmers who never used the throttle on NA engines. Started it wide open and shut it down wide open. Wonder why his repair bill was high?

 

[etpm]

Just a few thoughts of someone that has worked with farm machinery for over 20 years, small engines for over 15 years. Also studied recommendations of people that should know how to operate engines, manufacturers, and other "experts".

Most recommend to start engine allow a minimum time to run at about half throttle, 30 seconds to a minute, the go to work s l o w l y. Reason-- the engine will warm up faster doing work than sitting idle, wear is reduced as the engine warms up faster, fuel is burned more efficiently by a warmed up engine, pollution is reduced. On diesels recommend starting at WOT then pulling the throttle back as soon as it "hits" before the rpm starts to climb. This usually gives a full fuel load for quicker starting, some pumps has an excess fuel button for the same purpose.

If an engine especially a diesel is left to sit idling the combustion chambers cool down and fuel is not burnt efficiently or completely. You will get what is called wet stacking on most diesels that are not worked hard. Wet stacking is when unburned fuel collects in the exhaust system and runs out of the manifold, muffler, or exhaust connections, most folks will say "oil is leaking where the muffler connects to the manifold" nope not oil but diesel fuel that has turned black from soot. After an diesel has been warmed up and started it is usually not difficult or hard on the starter to restart, of course there are some that need glow plugged even in 90* weather. Shutting the down save wear on the whole tractor and reduces pollution.

As for shutting down the engine IF the tractor has been loaded do NOT shut off immediately leave it idle to half throttle for a few minutes before shutting down. Years ago some farmers had a problem cracking heads, found they would be plowing, or other heavy loads and just shut it off. Give the engine temperatures time to equalize and get rid of the hot spots before stopping the engine, then bring down to an idle for a minute before shutting down, especially the turbo needs the heat equalized and removed from the exhaust side or the seals coke with oil and leak thru the exhaust. Ever hear a turbo whirring after engine shut down? remember no oil no lubrication.

Even had some farmers who never used the throttle on NA engines. Started it wide open and shut it down wide open. Wonder why his repair bill was high?

Thanks all for the good replies. My Yanmar YM2310 doesn't have a turbo so no worries there about coking up bearings and since it's 40 years old no worries about modern pollution devices. But the other info is helpful and I think I know now how long to let it idle before shutting it down when the job requires manual labor such as shoveling. BTW, the manual says to use the decompression knob when starting, and even when cold, say 50 degrees F, the engine lights right up. So starting is easy on the starter and battery, which amazingly still holds a charge after sitting two years.
Eric