Deep mud/water!

I have a 2011 sportsman 800. Been using it for huntin, trail riding, typical stuff.
I’m starting to get a bit more into deep water/mud and other sticky spots I have no business playing in. 1st bought some tires. 28×10 & 28×12 mud zillas. By themselves they took my quad to a whole new level which made the going deep bug a little bit worse. Obviously I need a clutch kit, recommendations?

My main issue that I have noticed, outside of (it doesn’t quite float and I need to get snorkels) is that it dies on a regular basis when I get into deep water, and I’m on the throttle trying to keep the front end up. But it always starts back up. Now I can just idle and drive normally through water, exhaust buried, with no problem. I went through and sealed up most all of the electrical connections, so Now I’m stumped. Exhaust Pressure? I guess I don’t understand why it will idle under water, and start underwater, but I can’t be at half throttle under water.

Anyone got any ideas for me? I plan on stripping it down in the next few week and doing an overhaul on it and getting it snorkled.