3 pt lift-what is other knob and where is float?

[longleaf1]

I almost hate to ask this but I'm going to anyway. On my M5140, and I suspect on most tractors, there is the small adjustable sliding knob next to the handle for the 3 point hitch lift. I'm guessing you set this as a stop for the lift depending on what implement you are using. Is there a different purpose for this or did I guess right? Also while I'm asking about the lift...how in the world do you know when you are in "float" position? My loader handle has a difinite "stop" between lower and float but on the 3 point lift there is nothing. Thanks for any help.

 

[GWD]

The little locking knob on the 3PH lever mount should have a tongue that sticks out into the lever's path to limit the travel. It allows you to return to the exact same setting.

The "float" position on a 3PH is all the way down (lever all the way forward) since there is no resistance to an upward push on the 3PH's arms.

With the 3PH all the way down, try lifting one of the lower arms by hand. Both should lift together. Be careful of your back when trying this.

 

[oldcarkook]

You guessed right; it sets the 3 pt arm height. The 3 pt hitch is always in float because the weight of the implement provides the down-force. The round knob (between the seat?) will adjust the drag factor on the 3 point hitch bars; how fast they drop. When you have a heavy implement you might increase the drag so it doesn't slam to the ground when push the lever down. It only controls the downward force drag and not lift.
Here's a photo of the controls on my L3600GST with labels if that helps.
http://www.oldgmctrucks.com/photos/kubota/L3600GST_Controls1.jpg