If the center carb mixture screws are turned in all the way it does stall. It seems best idle is about 1 1/2 turns out. I’m still thinking the outboards will need to be jetted down. The Quick fuel plates looks like the way to go. This is a bone stock ‘70 440 HP, so I’m thinking .082 is to much. Since the outboards idle screws were staked, was that something the factory did or someone along the way?
