Fouling out

My Martinique been acting up again, and I am stumped as to why. It started two weekends ago after I dropped the boat in. When I accelerated up to about 10 mph (my guess, i have no speedometer), it would foul out really terribly, but at higher speeds it would run well. We tried replacing the ignition coil because it was not hooked up to the external resistor correctly, and that didnt help. Then it got a bit worse, it would do the same thing, but this time at two speeds.
Here is a little bit of background on my boat. I bought the boat in Febuary of this year. The engine was rebuilt not too long ago, and had only 10 hours on it since the rebuild when i bought it. Since then I have replaced the alternator(about 2 months ago) and rebuilt the carb(about 3-4 weeks ago). When I rebuilt the carb I found a lot of junk inside the float bowls, so I put an inline fuel filter in it, since it didnt have one to begin with.
Please help me with this; I am stumped.
Thank you, Matt.

If you had trash in the carb then you probably need to remove the tank and clean it. Radiator shops will do this work or you can buy tank liner and do it yourself.

There are a few things that you have to trust are in good working order when troubleshooting a carb and your tank is definitely one of them as well as the fuel pump. I removed the tank in my old boat and was surprised to find it probably only had a few more hours before it began to leak and dump gasoline into the boat. Be safe!

if you got a holley carb you would best to also replace the power valve. If your engine has backfired on acceleration you blew out the diapharm in the valve. Cleaning the carb & tank is a good idea also.

My vote is it's a carb problem. Probably a sticking needle valve, the power valve, or even a faulty choke. (In that order of likelyhood.)

In fact, I experienced the same thing with trash in my carb. You probably have more trash in the carb.