Bf30 carb cleaning no start

Late 90's era Honda BF30 on 18' pontoon boat.
Purchased past summer, new to me, but used to the world.
Rookie mistake of trying to start it without opening the fuel vent.
Sucked a whole lot of water through the fuel system from a fuel separator that was full of water.
Drained tank, flushed fuel lines, replaced water separator.
Engine would start on full choke and rev to 4000 rpm, but would not idle down. As soon as you tried to idle it would stall.
Replaced spark plugs, removed carbs and replaced the slow jet emulsion tubes as they were clogged, replaced all gaskets and o-rings. Cleaned the carb body with repeated trips through ultrasonic cleaner and blew out with brake kleen and compressed air.
All throttle body tiny orifices were verified clean and with good flow when sprayed with brake kleen.
Replaced the fuel filter and lines on all carbs. Pilot screw set to three turns out.
Reinstalled carbs on motor. Fresh gas in tank, vent open, pumped bulb until hard, set fast idle, turn over...no start.
Tried half choke, nothing...tried full choke , nothing. Verified fuel in carb bowls via drain. Tried electric choke..nothing. Just turns over. Safety lanyard is attached correctly and trans is in neutral.
Removed carbs, disassembled them to verify that the slow jet emulsion tubes were seated correctly.
noticed carbs 1 and 2 from the top of the stack were wet inside carb bowl from gasoline, but carb 3 on the bottom was dry.
I have the carbs back together and ready to be reinstalled, however it is raining now. such is luck.
Any input or ideas would be helpful.
Thanks

Wow! She's putting you through the ringer, ain't she?

Try opening the carb drain screws and pump the primer bulb to see if fuel comes out of each float chamber. The bottom sounds like it may have a sticking float valve.

Also, make sure the dashpot/check valve is installed correctly ie: allowing fuel to flow to carbs but slowing flow in the opposite direction.. Make sure it is clean inside and didn't get some garbage lodged in there.

Did you spray into the main air mix jet at the top of each carb? This is the small passage who's entrance is just above the carb throat inlet and leads to emulsion tube "T" at the top of the Venturi. This passage often gets overlooked during cleaning but is very important to the carb properly mixing fuel.

Make sure you still have good spark.

If the fuel chambers are filling and you have spark it should at least sputter and try.
If it still won't try and you know she's getting fuel, pull the plugs and see if they are wet or dry.
That might tell you which way to pursue the problem.

Good luck

Ok...finally got to the bottom of things. The fuel tank had new fuel, the water/fuel separator had a new cartridge. Just on a hunch, I pumped a quart of fuel from the fuel filter by the side of the engine and there was about 5% gas and the rest water. Pulled the tank and it had to have about a half gallon of water with 8 gallons of gas. The fuel/water separator cartridge was also full of water. Drained the carbs, flushed the lines, drained the tank, new filters and cartridge for the fuel/water separator, and why the heck not, new fuel lines and primer bulb. Hit the key and that baby fired right up on all 3 cylinders. Set the idle after after warm up and then set the pilot screw adjustment for each carb. Took it out on the lake and ran it for 30 minutes at different rpms and wot with no performance issues. Seems that the water tell tale is not "p'ing" as hard as it did, but got no overheating light. It is a mystery how that much water got back into the tank in less than 3 weeks. Previously I used ethanol mixed gas, this time, and for as long as I have the boat, non ethanol only. Might sit on the dock in the evening doing a bit of wabbit hunting....see what pops up..lol thanks for the input, two or more heads are always better than one! Happy Thanksgiving all!!

What do you have for a fuel tank? Is it leaking? The water had to find a path back into your fuel somewhere.

It is a Attwood 12 gallon tank without fuel gauge. Has ventable gas cap and the only other fitting is the fuel line feed. I put some dish detergent around the fuel fitting and pressed on the tank, no air escaped from that area. The cap sits up and the top angles away from the vent that is already higher than the cap itself. I don't think it was an act of gravity or nature, but more of a human made condition, so said Holmes to Watson.

All kinds of ways water can get in there. Water can be laced into the fuel from the source - small marinas that don't sell a lot of fuel are notorious for this. Old ethanol-laced fuel can separate. Constant condensation in the fuel tank will form water modules, which over time accumulate in the tank, etc. etc.

Even though I always use non-ethanol fuel, and have a built in 120 gallon tank, every year or so, after my boat has been siting. I tilt it on the lift, let is sit for awhile, then open up the fuel sender unit and snake a hose down to the lowest corner of the tank and pump out a gallon or so of liquid into a jar and let it sit for an hour or two to assess if there is any water in there. If so, I'll pump out a few more gallons to make sure I have all of the accumulated water out.