I used these at work. We have put a 9.9 Johnson and it does much faster on the water. Keep the chains greased. There are drain plugs under the back end. Those seats slide out in the back.

We ended up with the cheap version of the Argo, Recreative Industries maybe? but it was an absolute dog. I think it had a 20 hp motor in the rear and you could not turn it around in a parking lot. It was really loud, cheap muffler I guess. Steering was stiff as a board and used two levers kind of like a zero turn mower. We tried it in shallow water deep enough to float it, but the whole time it felt like it was going to turn over and pin us to the lake bottom. The Argo is a better brand for quality I am sure, but we eventually traded it for a Gator ATV. Hope you have better experience with yours.