1973 johnson 50hp won't go full throttle

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recently purchase 73 50hp...first time out wouldn't idle and warm up lever not working. i took carb/choke linkages apart and adjusted, cleaned carbs and had it starting and idling perfectly. got to the lake and it again started and idled out of the dock and when i gave it full throttle it only went to about half. throttle and choke valves were wide open but not responding. i can manually move throttle and it revs normally. could this be a bad spark advance setting?

 

[sea sprite]

Re: 73 johnson 50hp won't go full throttle

i should probably add that when first out with idling problems, the motor ran fine at full throttle. The problem only arose after adjusting the idle.