Oh yeah, mine did that and it was a sheered pin in the idler-wheel
where it connects to the shaft that goes to the lever arm.

I drilled it out and put a bigger pin in, though it's hard stainless
and the parts are small and hard to work with.

The belts go bad, too. You can get a new one from West Marine for $55,
or fir $8 from:
9.5AT5-750 Urethane Steel
Belt Corporation of America, 1-800-235-0947
http://timing-belt.com/urethane_steel_at5.html#top

Another common problem: The little wheels around the rim of the
mechanism break off. I bolted them in place using locknuts so they can
still rotate.

Here's the service manual: http://www.ganssle.com/jack/st4000.pdf

Jack
Sailing stories: www.ganssle.com/jack


otter wrote:
Thanks for the help! I have also posted on rec.boats.electronics

Does anyone know if the principle of operation is that the belt
disengages from the drive gear, or does it slip on the driven drum??!!
I am thinking that maybe the belt is old and doesnt have enough
stiffness to pull back from the teeth?

I have had the unit apart, the only thing that seemed a bit amiss is
that the idler wheel that is moved by the lever seems a bit sloppy--
maybe it is binding?

It's a weird one. I was hoping for a "Oh yeah, mine did that and it was
__________!"

Thanks again!

Otter
Catalac 8m
Currently in Cocoa, FL headed south