running issues

1974 15hp, electric start johnson, having issues running smoothly at full throttle, runs fine at idle, i've recently changed out the plugs, coils, fuel pump, fuel lines, added a fuel filter, had the carb rebuilt, added a four blade prop (that made a great difference getting to plane faster) and a new water pump. only thing left is the stater, condenser and magneto to change out. Question is which of these remaining 3 should i go with first, and by the way it only starts acting up after it warms up?

is there a diagram that shows these marks,

how does this help with smooth running at full throttle

You might try and put the 3 fin prop back on and see if this makes any difference. The link and sync that kimc describes above is to ensure that your spark timing is correct through all of the RPM ranges. If the arrow mark on the throttle cam is in the middle of the carbs roller, "just" as it hits the throttle cam (carb butterfly starts to open) then this is set correctly. The only other thing with timing is setting the points. They should be set for 0.020" gap (0.022" if they are brand new).

Perhaps it wouldn't hurt if you could describe a little more about the "issues" you have at full throttle. Is the motor missing, or surging or what? Please describe as best you can.

i went from a 3 blade to a 4 blade, its just a 12' aluminum john boat, the four blade made a big improvement with 2 adults in it, less moving around to get up on plane, after it starts to warmup running wide open "lets say about 2-3 miles down the river it seems that one piston starts to miss, i just finished checking and cleaning everything under the fly wheel found what looked like arc tracking across the fly wheel and one of two points not set properly, but now adjusted, all thats left to do now i figure is run it in the river for testing

it only starts to act up after running for a while, if i throttle down some kinda goes away but not completely, (look down below another post)