1979 175hp v6 idle problems

[nemer]

I have changed all needle seats, set the floats, synced the carbs, set the timming, checked the bleeder system, new plugs and wires. The motor will only idle down to 1100 with the muffs on. It seems smooth. Then I put it in the water and the back pessure is there, it begins to misfire in a consistant every 2 sec interval it pops real hard. I played with the timming and got rid of the misfire but the idle is to high. Last year I paid som smuck way to much to fix it. The idiot tried to power load my boat and dented it up. So going back is not an option. He said he repalced the trigger. Could he have done something wrong that is causing the problem? When I check the .461 for the pointer location, he was way off.