Very nice little motor. I have one in quite nice condition as well. How deep is the water in your barrel? It should be several inches above the A/V plate, otherwise it may take a long time to prime and start pumping. This should be avoided if possible. This motor is the first year for a thermostat, and that seems to slow down the appearance of water flowing out the outlet a little also. If you don't know the history of the motor and when the impeller was changed, I would advise changing it to avoid the possibility of the old impeller breaking apart and pieces clogging up the cooling system. Removing those chunks from some unknown place inside the motor is no fun. Ask me how I know.
The plastic drain plug gaskets work nicely in my experience. They are a lot easier to replace than the old fiber ones that often have to be picked apart to remove them.
The proper procedure for removing the fuel line is to loosen the cap on the tank to release the line pressure, then remove the line from the motor. I usually try to release the cap and run the carburetor empty before I pull the fuel line from the motor as well. There is often still some fuel that drips from the fitting even if that procedure is followed. I usually have a paper towel or rag of sorts handy to soak that small amount up. Thats especially important if you do what I often do and launch by hand from a shore. I remove the motor in the water before I drag the boat out since its a lot easier to move the boat without the extra weight of the motor on the transom.
There may be others with other opinions or input as well. I hope that helps.