All the carbs I've seen have a light spring returning them to idle if the throttle cable was disconnected. This functions to take up any slack in the connections, and also for safety to return to idle if the linkage came apart. No tension adjustment...If it doesn't work, the spring must be broken.
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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings