Motor loads up and bogs intermittently- Have to rev in neutral to clear carbs-HELP!!!

Okay Im about 1 boating trip away from emptying the clip of my .40 cal through the bottom of my boat in the middle of the lake!

1983 Mercury Black Max V*150

Im having an ongoing issue with the boat loading up randomly (mainly after running it for a while) where the motor will load to the point where I cannot even get on plane. I can floor it it it wont go passed 2500 rpm. I have to put it in neutral and rev it it until the RPM's eventually get up to 4500 before it clears out and then I can hammer it and it will run fine. When im neutral revving it, it smokes like no tomorrow and wreaks of raw fuel, but after 10 seconds it usually clears out. What else can it be???? below is the list of things I have done so far:

de-carboned the motor with sea foam.
changed spark plugs (about 50 times)
rebuilt fuel pump
rebuilt carbs (minus needle and seats)
all new fuel lines and bulb

my logic tells me that its not ignition related, since the WOT in neutral eventually clears out the issue. Could it be the timing? Again, logic tells me No because it doesnt happen all the time. either your timing is on or off, right? Is the fuel enrich solenoid faulty? (i think not because when it is acting up, I push the enrich button and it stalls out) are my floats set too high? Are my carbs jetted too rich? I checked my plugs and the insulators are mocha colored, so I know its jetted right at least at WOT...are my idle jets too rich? (I fish between 1500-4000 foot altitudes) What about my exhaust ports sometimes being submerged?

I am at my wits end. The only things I can think to do are reset my floats lower and check my timing before sinking the ship. I need an Outboard Intervention!!!

Thanks in advance to any and all responders!

Cheers

Re: Motor loads up and bogs intermittently- Have to rev in neutral to clear carbs-HEL

1) get a manual, (2) check ignition when it does this as you may be dropping a bank due to a weak stator(3) replace needle and seats and float test floats as you may have one or more gettting heavy from ethanol damage(4) check the recirc valves for blockage (5) leave engine trimmed up with relief above water till you get ready to plane off, put it in gear and trim down while accelerating

Re: Motor loads up and bogs intermittently- Have to rev in neutral to clear carbs-HEL

UPDATE- after many hours of troubleshooting and help from member J_martin and others I finally fixed the problem. It turned out that the port bank switchbox and the low speed stator were bad. Only 360 dollars in parts and and about 1 hour of personal install time and boom, the problem is fixed! The motor purrs like brand new. What I thought was the motor loading up was actually the stator not firing. It acted as if the carbs were cleaning assuming that the gradual climb in rpms got the motor working passed the low speed coils to the high speed. I hope this thread helps anyone else experiencing the same issues.

Tight lines.....