I just picked up a older Asplundh wood chipper with a Ford striaght six engine. To get it running I had to replace the fuel pump, do some fabrication on the chip blower, etc. I had it running and warmed up and started to engage the hand clutch slowly. It went in and all was well. I went to disengage and it wouldn't go. The hand lever moves slightly and the shaft to the throwout bearing is lubricated and fine. I can really push on the lever to disengage the clutch and I can stop the drum from turning, but it won't stay disengaged. The clutch is acting like it is stuck engaged. Any thoughts, other than totally dismantling the clutch assy? This bargain I bought is becoming more of a chore than anything!!!