Loball, that is indeed a 1969 55hp Evinrude. I have one that works great. If you do not know anything about troubleshooting outboards or how to research things on the internet, you are going to be frustrated for a long time. Each and every motor is unique, with it's own set of issues. No one could magically tell you exactly each and every thing that is wrong with your engine, without actually having hands-on and performing a series of tests and checks.
Outboards need 3 things to run. Fuel, Fire(spark) and Air. The easiest thing to check is spark. Take one of the spark plugs out and connect set the metal (like near the threads) against the block of the engine, with the spark plug wire connected to it. Turn over the motor. If you are next to the spark plug, you should be able to see a thin blue spark at the tip of the spark plug. If you see it, you have spark. If you do not, research what causes spark issues with these motors (the ignition module is probably the biggest problem). Put the spark plug back in, btw... Now you can check fuel. Use a can of engine starting spray and spray about a 1 second spray in each carburetor. Now try to start the motor. If it kicks or starts for a few seconds, your engine is not getting fuel. Bunches of things to check here. Fuel filter, carb rebuilds (all three), bad fuel line, bad fuel pump, bad fuel tank, etc... This motor also has some safety features which can drive you crazy. The boat has to be in neutral to start. It will also not start, if you set throttle too high.
In my opinion, if you are an experienced mechanic, then you can look up how to troubleshoot outboards. Then get yourself a service manual for this exact motor and use it to work out everything that's wrong. That's if your patient and determined to do it by yourself...
If you are not an experienced mechanic, I would seriously consider taking the motor to an actual outboard mechanic and have them work on it. These motors are really a nice motor when they are all working properly, but have a lot of linkage, etc., that has to be precisely set and configured in very precise ways.
Good Luck,
RDH2059