potentiometer

[jc]

I have a LT 40 hydraulic with a Kubota diesel and setworks.  A while back, all of a sudden, I had to turn the potentiometer halfway to max to move the carriage forward.   Everything works fine except for that.  I replaced the potentiometer and cleaned and lubed the drum switch.  The head returns at normal speed, and the head moves forward normally except for having to turn the potentiometer a lot farther to the right than normal.  I checked the brushes in the motor about 300 hours ago and they were fine.  Any help would be appreciated.

[BBTom]

I had that problem once and spent two days scratching my head--then figured out the set screw on the potentiometer knob was loose. 

Hope yours is just as easy to fix

[pineywoods]

That's a classic symptom of a bad head support bearing/roller. Drop the head down on a block of wood to take the load off the rollers, then check all 4 .

[paul case]

welcome to the forestry forum.   pc

[Magicman]

Welcome to the Forestry Forum jc.  I agree with pineywoods about checking those cam follower bearings.  Another thing to look for is a splinter wedged somewhere close those bearings.  Look closely, splinters can hide.

If you disconnect the two wires from the power feed motor, the carriage should roll smoothly and easily.  You do have the operator's end slightly higher than the rear don't you.  You do not want to add climbing a hill in addition to sawing to the power feed.

The next thing is your power feed sprocket(s) bearings.  You will need to disconnect the power feed chain to verify that they are free wheeling.

Keep us updated on your progress.  It will help someone else.