Rough Running after freeze plug replacement

I have an 87 Martinique, I put it in this year for the first time, the boat was winterized, I put all the plugs in and took it to the lake. It started right up and I idled out to let it come up to temp. I then ran it for about 15 minutes, boat ran great, no problems at all, smooth as always. I got to the dock and let it idle while I tied up. Shut it off and then went to restart it just for the heck of it because we were about to take it back out after dinner. It wouldn't start so I pull the shroud to find it almost completely full of water. Immediately bilged it and took a look. One of the freeze plugs above the starter was gone. Im not sure if it had been gone the whole time, but I didn't notice it before I left the trailer. Anyway, I put a temp plug in to get me through the weekend, boat started right up, so I let it sit and idle for about 10 minutes. No issues, temp was good, oil pressue good, etc. I idled away and it started running rough, really rough. Now I can hardly get it in gear without dying.but in neutral it revs fine, under the load it won't take it. It backfired a couple of times and there is a very strong smell of gasoline from behind the boat, more than the normal old exhaust smell. Not sure what has happened to it. Its not old gas... because it ran perfect from the trailer to the house. No water in the oil from what I can tell, oil looks perfect, not milky or bubbles...
I have no clue whats up with it... need new plugs??? is my first thought...

I winterized it, just draining and antifreeze... I've done it that way since we got it in 87, never had any problems, bought it up at midwest CC in angol, IN, ... and the winters there are much harder than down here in AL...
I've been messing with it all morning, checking and rechecking the oil for any signs of water. No sign of water at all, nothing milky, no bubbles, the oil looks perfect.
I read almost the entire SOS post last night til about 1 am. I'm praying its not gonna drag out like that. It sounds "literally" like it has bad gas. Except bad gas will let it run good sometimes then horrible most of the time. Bud the "sounds" are the same.

Forgive my lack of engine knowledge, but here's one more bit of info... we had Geoff at Midwest CC change it from points to electronic ignition... years ago, just and fyi...
If I'm going to look for moisture, walk me through it please.. so I don't make this worse:) I'm pretty handy, but I probably know just enough to be dangerous"to myself" that is :)

David,
Have you checked the plugs yet to see how they look? With the distributor being converted, all you can do is open up the cap and see if there's any condensation in it.

Has the carb been rebuilt? Do you stabilize your gas during storage?

Your draining and then pouring in the antifreeze is the only way to go. Some will pump though without even draining but it's risky due to the potential of mixing with water. RV antifreeze doesn't like that!! You do probe the drain holes with a wire just to make sure you don't have sediment plugging it up correct?

Get some photos and text submitted for the diaries.

replaced the spark plugs, drained the fuel filter, it ran a little better, it will idle now and thats it. No more than about 1200 rpms. it sounds like the engine is knocking deep inside. It doesn't knock consistently, every 4 o 5 seconds... I'm not getting a good feeling about this... Also, there is still a very strong smell of fuel, much more than usual. Still no water in the oil, so hopefully that is a plus. It feels like the motor is not getting fuel, but not sure, any thoughts?

Pete,
the carb has not been rebuit for a while. But thinking about it now, I bet your right. Too much fuel... I know nothing about carbs though... or adjusting..

no gas coming out of the vent tubes, i just went out and messed with it a little more, it will idle ok, when you put it under a load, around 1200 rpms it starts to backfire, I'm not sure how to check the floats, I've been trying to read online about it, but not really sure yet...

have you checked the fuel pressure at the carb?

My fuel pressure jumped up to 7 psi with a new pump.    It was about 4-4.5 psi before on the original pump.

That has made a huge difference in running for me already, although i have yet to water test it.