Hi folks. I've searched thru the posts and can't find anyone else that's had this problem but the throttle on my stock 86 sammy sticks on occasion. It happens when I'm on the highway, usually climbing a grade, and the throttle is wide open or close to it. Turning the key to shut off the motor is the only thing to do and doing so solves the problem -- until it happens again. It has happened 4 times now. I've cleaned the carb and all the springs but that didn't solve the problem. Does anyone have an idea of what is happening? 

It sounds like the carbs butterfly may be drivin overcenter, ie too much travel. I would look into adjustment of the pedal/throttle travel

Thanks talonxracer. I'll have a look and see if I can adjust that.

Possibly the cable is going. They can hang up when they are starting to go. Especially when they are held wide open for a while. The cable can cut a groove in the plastic tube.

Disconnect the cable and see if it is the carb or the cable.

If it is the cable, you will be able to tell easy. Keep tension on it when you check though since it won't have the same drag as when hooked up.

If it is the carb, look for carbon buildup under the butterfly. Most carbs have a stop for the butterfly (both WO and idle), but I haven't checked these close enough to tell you.

When mine did this I replaced the throttle cable. It was starting to fray under the dash. I've had no problems since replacement.