2000 mercury sporadic miss and surging

[Miorgsteel]

I have a 2000 mercury baby L3 40hp. Idles fine and starts fine. At 1/4 throttle and up it has a bad miss and surges. The miss is sporadic. The surging is all the time. I'm not a marine mechanic but I'm fairly mechanically inclined.
New fuel lines and filter.
Carbs rebuilt
New gaskets everywhere
Carbs synced
Ignition timing checked
Cdms resistance checked
Trigger resistance checked
Spark on all 3 cylinders almost will reach an inch.
I'm lost...

 

[fastjeff]

Water getting in the cylinder(s)?

Jeff

 

[Docksidemarineservices]

You need a vacuum mate to sync this engine while the boat is floating in the water...... to get it right.