Kubota Grand L3940 Auto Throttle adjusted - Works great!

[beppington]

Tonight I finally got around to adjusting my L3940's Auto Throttle, & it works great now! :thumbsup:

For those that don't know, the Auto Throttle is set at the factory to immediately wind the engine up to full throttle (2700 RPM) just about the moment you touch the HST pedal. The engine's screaming even though you're barely crawling. I just don't need that, especially since I almost never set the RPM above 2000 (for anything, even PTO stuff). This didn't interest me, so I've never used it again after trying it once, all the while planning to try my hand at adjusting it per instructions here on TBN (crazyal & TalonDancer).

Using crazyal's picture below, I adjusted the rearward silver* nut in the picture almost all the way rearward, which caused more slack in the Auto Throttle's cable, then re-tightened the front nut. The additional slack of course makes the HST pedal engage the throttle a little later than it originally did.

This causes the RPM to rev up to about 2000 RPM when I stomp on the pedal, about where I normally set it manually. Now I'm looking forward to using the Auto Throttle whenever I'm not using the PTO :thumbsup:

* I believe it was the silver one. However, it's easy enough to tell. With the tractor off, engage your Auto Throttle, then press the HST pedal with your hand while looking at the area in the pic: Whichever one pulls the throttle is the HST Auto Throttle cable.

 

[crazyal]

Bet you are wondering why you didn't do it sooner. :thumbsup:

 

[Johnbro]

gonna do this Real soon Now. But you really should re-think about lugging your engine. Those engines are INTENDED to be run at full throttle--I rarely run mine below 2000 rpm, and our Kubota ZTR never mows at less than WOT, per the manual.

 

[beppington]

Bet you are wondering why you didn't do it sooner. :thumbsup:

You know, I actually did take a look one time a couple months ago, but had it in my mind that the adjustment was done under the floor, below the HST pedal ... couldn't find anything throttle under there that looked very "adjustable" ... & gave up back then.

 

[crazyal]

gonna do this Real soon Now. But you really should re-think about lugging your engine. Those engines are INTENDED to be run at full throttle--I rarely run mine below 2000 rpm, and our Kubota ZTR never mows at less than WOT, per the manual.

Before I adjusted it and before I was use to HST I would have the engine idling and set on the pedal only to dog the engine for a few moments until I remembered that's not how HST works. If I'm working the tractor hard I don't use the auto throttle, to me it's for things like driving where you're not going to bog the engine down.

It's real handy when you are often coming to a stop where the tractor will sit for a little bit of time. There's no reason to have the engine running at near WOT when it's just sitting there not doing a thing. IMO Kubota sets it up so you wont bog your engine down because they don't know how the operator will use it or what the tractor will be pulling.

 

[slowzuki]

Nah the Kubotas also come with gear transmissions and the whole rpm range is used. Not a worry.

gonna do this Real soon Now. But you really should re-think about lugging your engine. Those engines are INTENDED to be run at full throttle--I rarely run mine below 2000 rpm, and our Kubota ZTR never mows at less than WOT, per the manual.

 

[Grateful11]

>"the Auto Throttle is set at the factory to immediately wind the engine up to full throttle (2700 RPM) just about the moment you touch the HST pedal. The engine's screaming even though you're barely crawling."

Ours must not have been setup like that from factory because it definitely doesn't rev to 2700 rpm's the instant you touch the HST pedal. Ours is used everyday for loader work so I'd rather have the rpm's up a bit at the slower speeds. Seldom do we see it rev over 2100 or 2200 rpm's when moving round bales.

 

[ejkessler]

My AT goes to around 2K to 2.2K when pressing the pedal initially and goes to about 2.5K to 2.7K only at full pedal. Sounds like there are differences between who set them up. Wonder if it's a factory or dealer adjustment. The point about not lugging is well taken as is not high revving when not needed. I use all of the above mentioned tactics when running my tractor as well. Keeping in mind to run the engine at high RPM's under load and not when just maneuvering and traveling between locations.