Does it stall when going into reverse? Do you have a "shift interupter"? Many threads about this at BoatUS.
What carb? Do you "prime" your engine
before starting (if it has an accelerator pump)? Check that the choke is free/closed.
If the stalling is caused by fuel starvation, feed the carb fuel from an elevated fuel source. This removes the boats fuel delivery
system but not the float valve. Check the carb's inlet filter (screen).
What solinoid did you disconnect?
Carbs fail from being dirty and defective float/valve, and can be rebuilt.