Reply To: Johnson JW-13 3 hp Seahorse

[Don]

OK, well I am assuming you want to actually run and use the engine, not just display it, correct?
So, let’s begin at the beginning…How much experience do you have working on outboards?
The first place to start is with the fuel tank, open the cap, have a look and a sniff inside…Is the tank clean, free of varnish and rust? Hopefully, because the tank is pretty much useless if it can not be cleaned out inside with relatively mild solvent. Don’t use anything too harsh that you might spill on the paint.
Next, you mentioned the compression seems good. Pull the plugs and check compression on each cylinder. Don’t be concerned when you see relatively low readings, 70-80PSI, this is normal. The important thing is that the readings are about the same on both cylinders. Next, temporarily crack open the large lube drain screw on the bottom of the gearcase. You will probably see relatively dark gear lube, which was normal for the time. Newer lubes are more golden in color. Milkshake colored lube is concerning, raw water is trouble. You only need to crack the screw open for a second or two to get a read on gear lube condition, no need to drain it out at this time…..Reinstall the screw after a few drops have dribbled out.
Next, you will want to have a peek at the ignition…Usually, an old low hour engine like this has its original coils, which have probably cracked over time and must be replaced. You can peek inside without removing the flywheel completely. Simply remove the four screws that secure the recoil starter, now you will see the top of the flywheel….There are three flat tip machines screws that secure and inspection cover, remove those screws and the two cover plates. Now, peek inside, are the coils all cracked up? If so, the ignition will need to be overhauled.
You will probably need to pull the carb apart, clean it out and rebuild it also, there is a tank filter and valve that should be removed and inspected also…
Finally, you will want to remove the gearcase, inspect and replace the rubber water pump impeller….
Needless to say, this is just a quick outline of things you will need to inspect and service in order to make this engine a “reliable daily runner”. We can go into more depth as you approach each project. For now, do the compression test, inspect the tank, and gear lube….Don