1980 evinrude 35 hp bogging down under heavy load

I have a 1980 evinrude 35hp electric start, remote steer motor. The motor has 120 psi compression on both cylinders and has good white/blue spark that will jump a 7/16' gap. The motor will run great on my boat (15' sea nymph deep v) with no issues if I am alone in the boat. If there is another person in the boat it starts to act like it is starving for fuel as it is about to come on plane. The motor will surge or bog down and I can only go about 7 mph before it will act up.
If I bump the key in to activate the electric choke a few times it will clear up an take off on its own like nothing is wrong and then run fine. When it is bogging down squeezing the primer bulb does nothing.
The boat has new Primer bulb, fuel lines, fittings and fuel tank. The carb and fuel pump have been cleaned and rebuilt.
Any ideas a to what would cause it to run fine with one person in the boat and then bog down under a heavier load?.

The hull is clean. I don't have a rpm gauge hooked up to motor. Would have to buy and aftermarket one and install. I have done the link and sync but only by eye. If anything It is probably openjng too much between the marks. I should use a clip as you suggest to do this more accurately. If the butterfly opens too soon would it cause my problems?

The plugs look good. The motor doesn't have power trim. It has the pin the needs to be removed and placed in a different hole to adjust the motor tilt/trim. I'm sure it is not a trim issue because it only bogs down with a heavier load until I push in the key to activate the choke. After a few times it will run fine like it does with only one person in the boat. The tilt/trim is in the optimum position, I have tested all the different pin locations. Thanks for the replies so far.

I'm pretty sure I have the butterfly opening a little too much when I tried to sync the throttle. Would this cause the problems I am having?