Re: What do I have?

[Don]

OK buddy, not so fast now.
Yes, those outboards are two stroke, they only get lubricated by the oil mixed with the gas. I can’t speak for the merc, but those johnsons need a minimum of 24:1 fuel/oil mixture. In other words, one quart of quality TCW3 outboard oil mixed with 6 gallons of regular gas. We know the engine will fire up, but how well/reliable will it be in its present condition? You have to decide if you want to run it "as is", or make a reliable daily runner out of it.
If you want to run it "as is", you will need to check/change the gear lube first. There are two large fill/drain screws that need to be removed on the gearcase, one down low on the skeg, the other is probably just below/above the horizontal plate just above the propeller. DO NOT remove the little phillips screw near the lower oil drain screw. The phillips screw secures internal shift linkage, removing it will cause the linkage to come apart inside the gearcase. Have a look at the oil that drains from the gearcase, is it milky? Is raw water present? Did anything at all drain out when the screws are removed? There is one seal/washer used on each drain screw, it is important that each screw has one and only one seal washer present. This is an easy mistake to make, sometimes the seals stay in the housing when the screws are removed. Find both seal/washers after the oil has drained. Leave the washer/seal in the housing if that’s where you find it, trying to pry it out will probably ruin it. Again, messing this up will create an oil leak when you refill the gearcase.
You will need to purchase a 32oz tube of gearlube to refill the gearcase. DO NOT attempt to fill the gearcase from the top/vent hole, the oil must be squeezed in through the lower hole with the top plug removed, the gearcase is full once oil starts flowing out of the top/vent hole while squeezing the oil in through the lower hole. It is probably best to have an assistant for this operation.
Have the assistant reinstall the top screw once oil starts flowing out of the top hole, do not remove or release pressure from the lower hole while the assistant is installing the top screw. Once the top screw is reinstalled, it will create a vacuum making it easier for you to remove the tube and reinstall the lower screw without losing much lube.
What type of fuel tank does the engine have, single or dual line? Check the bottom of the fuel tank for gunk or rust, you will need another tank if either condition is present. If the tank is OK inside, add a few gallons of regular fuel, then add the quart of TCW3 oil, add the remaining four gallons on top, this helps mix the fuel/oil properly. Give the tank a shake to ensure proper mixing. Remember, this is a two stroke, it will run for only a few minutes with no/not enough oil before it seizes and game over.
Once the fuel oil is mixed, connect the fuel line to the engine, pump up the button/primer bulb to ensure there are no fuel leaks.
The engine must be run in the water. The water pump is a rubber impeller that needs water running through it for proper lubrication. Running the engine for just a minute or so with no water going through the pump will melt the water pump impeller.
The engine must be run in a tank/barrel of water, the water level must be a few inches above where the gearcase is joined to the exhaust housing in order for the pump to work properly.
Now, go ahead and start the engine, there is a hole half way up the back of the exhaust housing where water should be spraying out. If no water is spraying out, shut it off before it overheats.
Considerably more work is required if you want to make this engine a reliable daily runner, first do a simple compression test. You will need to remove the gearcase and replace the rubber water pump impeller. You will need to clean and check the ignition components under the flywheel, which requires a special puller to remove it properly. You will need to disassemble the carb, check and clean it, replace gaskets/float/fuel lines. You will also need to check the tank fuel line and primer system, these items might need work as well.
And yes, it does look as the engine block was replaced/rebuilt. It is hard to know whether this is a good thing or not, it all depends on what caused the failure and who did the work.