I recently got an '85 Spree running after it had sat untouched for 14 years.
It was running pretty strong up to about 25 mph, then would begin to bog. So
I decided to take the carburetor off and clean the jets again.
This went fairly smoothly, but when I had it all put back together again, and
went to start the thing up, I noticed the THROTTLE was no longer working
properly. I get no "spring" action when I twist the grip (there's no
resistance when i twist, and it doesn't snap back to idle). So I again
unscrewed the throttle body from the carburetor, and found that the spring
was still there, and I got could "spring" action when I twisted the grip.
It's only after I screw the throttle assembly back into the carb that I have
a problem. I also have the impression that the throttle is stuck wide open,
because when I finally did get it started temporarily, the engine was racing.
I've looked at the whole throttle assembly closely and can't for the life of
me figure out what's wrong, especially since I did no tinkering with the
throttle accept for removing it from the carbureter.