You will probably expend more effort, time and experience more problems trying to adapt your weed wacker gas can to accommodate your outboard.
Go to a Wal-Mart or Academy store and purchase a marine 3 gallon fuel tank, fuel adapter for Evinrude/Johnson (to screw onto the fuel tank) , and complete fuel hose set up for a Evinrude/Johnson with fuel connectors and both ends.
You need the fuel adapter because most of the tanks that are sold are universal tanks.
**Don't forget to open the vent screw on the gap cap to allow air enter the tank when running your motor. If not you will shortly have fuel starvation issues and your motor will run poorly.*** The fuel bulb is usually connected near the tank and there is an arrow point the direction of the fuel flow to the motor. Pump the bulb until it is somewhat firm, choke the motor, crank her up, push in the choke and off you go.
Oh, here is a link to some good reading for your motor. It will tell your how to basically maintain and repair your motor and a little more if need. It will give you your fuel to oil ratio as well.
https://www.sschapterpsa.com/ramblings/OMC_6hp.htm
Here is an online parts store and a electronic parts diagram for your motor as well.
https://www.marineengine.com
If your motor was made after 1965 then your fuel oil ratio will be 50:1. That would be 8 ounce of TWC-3 grade 2 cycle marine oil to 3 gallon of regular 87 octane gas. Put your oil in the tank and fill it with 1 gallon of gas and mix it up well and put the remainder of the 2 gallons and shake it up a little for a good even mix.
Happy motoring and good luck fishing.