Idle Speed...why so fast??

[wowwee]

Hey There, I've got a 2008 model B2320. Once it's warmed up the lowest it will idle is about 1100 RPM. Anyone know if I will do any harm adjusting the speed a little lower? Maybe Kubota has to set it there from the factory just to meet emmisions standards?

Thanks, Dale

 

[yooper jim]

Set the idle lower and it will shake it's self to death. At least that is what I've heard. BX 2660 idles at 1250.

 

[timswi]

Set the idle lower and it will shake it's self to death. At least that is what I've heard. BX 2660 idles at 1250.

Yup, that's true...You want a smooth idle or it will shake itself to pieces.

 

[RadarTech]

I am constantly amazed at things like this..

1100 RPM to be smooth...


wow....

J

 

[rswyan]

Anyone know if I will do any harm adjusting the speed a little lower?

Hmmm .... well, it certainly may be true that a very rough idling engine "might shake itself to death" ..... but if I had to guess ....

It probably has more to do with the inherent nature of diesel engines ...

Diesel engines - at least the ones that I'm familiar with - tend to be somewhat cold-blooded creatures (possibly because they are so efficient) ..... and they really like to be worked to remain all nice and toasty at proper operating temps .....

Since a diesel engine runs as a consequence of the heat generated from compression of air igniting the fuel, one could theorize that below a certain speed a diesel might not generate enough heat to fully combust-ulate the fuel being injected into the cylinders .....

If the fuel is not being completely combust-ulated, then the un-combust-ulated fuel would likely go somewheres ....

..... and diesel fuel, being a solvent-sorta liquid (kinda) might tend to wash down the cylinder walls (gravity being what it is and all) - removing good stuff like, oh, say .... engine oil, which is intended to lubricate things - and then just keep right on going .... down into the crankcase ..... which might possibly result in fuel/oil contamination:

Crankcase dilution

.... and other similarly nasty stuff - like wet-stacking (otherwise known as mung and drool ):

Wet stacking

I can tell you for a fact, that the above is exactly why my dealer, when he set up our B2910, set the idle to 1200 rpm .... (I know - because I asked .... )

It's also the reason that the little 2.7 liter, 5 cylinder Mercedes diesel engine in my Dodge (Mercedes) Sprinter has an Espar D5 Hydronic coolant heater installed from the factory - this is a little heater that burns diesel fuel (kinda like a mini-torpedo heater, only it heats engine coolant) in order to keep the engine coolant at operating temps in cold weather, when the vehicle is idling alot (Sprinter's factory idle is around 700 rpm, is controlled electronically via the ECM, and cannot be adjusted manually - other than by the use of an "idle stick"), or being driven stop-n-go .... and won't stay at normal operating temps .....

Me personally ? .... given the possible alternatives, I'd learn to love the sound of that little orange oil burner, sitting there purring at 1100 or 1200 rpm ......

 

[RickB]

There's a two word answer:

Emissions standards.

 

[Egon]

In colder areas many diesel P/U's that do a lot of idling have a fast idle controller installed so the engine will stay warm.

Chances are the engine needs to be at a certain running temperature before a complete combust-ulate:thumbsup: can be acheived!

At -20C I've gotten quite cold while waiting in a line up in my truck.

 

[kuboman]

I have adjusted down every tractor I owned including all my kubotas. No they will not shake themselves to death. They all have a "sweet spot". My 2620 idled real nice at 800 rpm. Play with it and find you tractors spot. A slower idle will not hurt anything.

 

[timswi]

I have adjusted down every tractor I owned including all my kubotas. No they will not shake themselves to death. They all have a "sweet spot". My 2620 idled real nice at 800 rpm. Play with it and find you tractors spot. A slower idle will not hurt anything.

True, as long as you find a smooth spot...That violent shake is too much to take, at least for me. I don't like seeing the air filter etc shaking all over the place.

My BX will shake it self to pieces at base idle..The RTV1100 has a higher base idle so it appears. The 1100 has no shake at all, and it has the same basic drive train.

 

[AceDeuce]

My BX shakes so bad at idle it broke [from fatigue] one of the 1/4" steel brackets that supports the counterweight over the valve cover---I was amazed. Now I don't ever bring it all the way down. Instead I keep the RPMs up enough to make it run smooth. My uncle's 25 yr old 3 cyl. L2250 idles VERY low (only a few hundred rpm) and runs smooth as a baby's but. Go figure.