600 variable speed control valve

[mark18mwm]

Any of you guys with 600/610's ever have trouble with the variable speed control valve suddenly getting "loose" and the machine shifting into high speed? My control handle just falls forward and it goes into high. I can pull back on it and it shifts back down and will stay there if I hold the handle but when I let go, it falls forward into high. I never had the valve apart before but it looks like a simple spool valve so I guess I'm not afraid to tackle it but was hoping you guys might be able to give me some tips on its overhaul before I dive into it. My guess is there might be a ball and spring in there that locks the spool it in place when your done moving the lever and I'm thinking that spring or ball might be the problem. Any ideas or advise?

 

[mark18mwm]

Got it, the washer on the screw on the back of the spool wore out and pulled thru the spring. Simple fix, new $.05 washer and ready to go.

 

[6brnorma]

Got it, the washer on the screw on the back of the spool wore out and pulled thru the spring. Simple fix, new $.05 washer and ready to go.

Thanks for posting that one Mark………I had never heard of that one before and guessed it was something of that nature.