Starting Procedure

[David_Kb7uns]

It may also be tied into emissions these days. The quicker idle will build heat up faster and have more complete combustion.

David Kb7uns

 

[Gale Hawkins]

The manual states a working speed of 2200 RPM when using the backhoe on our JD. The engine cold sounds the smoothest at about 1100. I have never had a 3 or 4 cylinder tractor that I ran at more than 2200 RPM under load. The JD will turn up to 2800 but I do not consider 1400 to be half throttle. I do like to be run with my tongue hanging out so I do not do it to my equipment.

Now if I am about to get stuck or something then going full bore is not a problem for me but that is like 30 seconds in most cases.

 

[poldies4]

Start mine at Idle and I too have the 3 second pulse and a little smoke. how many hours do you have on it?

Mine has 18 hrs on it

 

[TripleR]

Thanks TripleR, funny how little things like that don't matter till they matter. Is it a diesel thing, or a Kubota thing? This is the only diesel i've ever had.

Poldies4, unlike some on here I do not consider myself an "expert" because I have owned some tractors for over fifty years nor do I do things because my "daddy did" and it worked for him. I go by the manual that was written by the people who designed and built these and whose reputation rides on the performance/longevity/dependability.

Would you want a factory trained mechanic working on your tractor who goes by the shop manual or would you prefer someone who have worked on a few engines who didn't know the exact valve settings, lash or torque and just set it where it worked "OK" on something else?

As to it being a diesel thing, no as my son's truck doesn't need to be warmed up that way nor did my dads dump trucks or tractor trailer rigs which is why I go by the manual. I doubt there are any "universal rules" for gas or diesel engines. Heck, go check out a gas or diesel powered generator WFO the minute they start. Nope I sure am not an expert, so listen to those who are. YMMV

 

[kuboman]

Engine start is the most important few moments in the life of an engine. Think about what happens when you start your car or truck. They are programmed to start and fast idle immediately. You might think that this process is harmful but quite the opposite is true.

The oil pump does not directly lubricate many of the parts inside an engine. The oil that is flung off the crankshaft accomplishes this task. At a speed of 1800 RPM, this oil is quickly spread to all areas inside the crankcase. If starting at idle speed, this process takes much longer.

I always start my tractor at near half speed, and avoid idling it after it has warmed up.

Now reading this just sends shivers up my spine.
All these engines are pressure lubricated, there is no flinging per-say. Revving a cold engine with heavy thick oil only wears out the parts of the engine that the oil is slow to flow to, cam shaft, top end bearings etc. The best starting procedure is to start it as slow as it will comfortably run and idle till there is some warmth through the whole engine block.

 

[radioman]

same here- bump up the idle a hair before starting, glow, start. As long you get used to the right throttle sweet spot for smooth idle , you can do it everytime.

You asked about the speed, the BX goes nowhere near 10mph! To even get at 8mph, you need to be in rabbit gear and rated rpms (that is nearly WOT!!!) I hate running WOT when just traveling, seems like a waste of power and fuel.

The BX wasn't designed for road travel since it travels sooooo slow!! I done it once, and never will do it again! it takes tooo long.

 

[Dirk Lately]

Now reading this just sends shivers up my spine.
All these engines are pressure lubricated, there is no flinging per-say. Revving a cold engine with heavy thick oil only wears out the parts of the engine that the oil is slow to flow to, cam shaft, top end bearings etc. The best starting procedure is to start it as slow as it will comfortably run and idle till there is some warmth through the whole engine block.

Then why does my manual say to start at half throttle? Is Kubota practicing planned obsolescence? What you say sounds reasonable to me, but presumably Kubota knows what they're doing...

Although I know what my manual says to do, I find I can't start at such a high rev. It just seems too abrupt, or something. We've gotta ease into things, you know.

 

[Grateful11]

Of our 6 tractors 4 are diesel and we've never done more than just a hair off
idle when cold starting. Our Case IH 5140 is a 6 cylinder Cummins and it doesn't
have glow plugs, it takes about 1/2 sec. to fire off at idle. The IH 686 has no
glow plugs either, fires off in about 1 sec., now the IH 574 usually takes about
2-4 secs to fire off in 60 degree weather.

poldies4: I noticed that 1/2 throttle thing in the manual our new L3940.

 

[KeithInSpace]

They are programmed to start and fast idle immediately.

I read you post and thought to myself that I'd been doing something wrong all this time.

I start at idle, then bump to just off idle for warming. Hasn't ever complained. Of course at 300 hours, I probably still have hone marks on the cylinders...this whole issue won't become evident until you have a 3,000 hour engine that, for some reason, won't make it to 4,000 hours.

Back to the fast idle thing, though. My Expedition goes to ~1,100 RPM instead of an ~750 RPM idle when I start it. Considering that engine redlines at 5,000 RPM, that is approximately 8.235294% throttle.

I'm not certain what the BX correctly idles at, but let's call it 1,000 RPM with a 3,200 RPM redline. Half throttle would then conceivably yield half RPM, or roughly 2,100 RPM.

Relating this back to my truck, fast idle would then be 2,875 RPM. I can tell you this: If I sat in my driveway and intentionally held my truck at nearly 3,000 RPM, my wife would come outside from whatever she was doing and wonder what the heck I'M doing.

Idle doesn't feel right, necessarilly, but 1/2 throttle doesn't feel right either.

I'm going to stick with something around 8.235294% throttle and let you know how it's working out at 3,000 hours. If history is any measure (4 years of ownership I currently have 299.9 hours), I'll hit that in another 36 years.

 

[TripleR]

Our renters often keep some of their tractors in our barn and while I don't know what RPM'S they use, I can guarantee it is no where near idle. One of their utility tractors is an old IH1486 and they have John Deeres from 47 to 325 HP.

As mentioned previously, it will take LOTS of hours to tell which is "best" as none of these are going to have early catastrophic failure no matter how you warm it up, just be sure to warm it up.