There is no such thing as a 1959 15hp Evinrude/Johnson model. I suspect you have a older 15hp that incorporates the dual fuel line setup. What is the model number of that engine?
The fuel tanks would be pressure tanks, not compression tanks. Your mixture of 24/1 is correct. Always put some gas in the tank first, then the oil, then the rest of the gas.... If you put the oil in first, you run the risk of having raw oil fed to the carburetor.
Being in storage, if you still have compression and spark, the problem is usually a fouled carburetor, in which case, clean and rebuild it. Rig a spark tester where you can set a 1/4" gap for the spark to jump... the spark must jump that gap with a strong blue lightning like flame, a real SNAP! NOTE... using spark plugs to test the spark is a waste of time, the 1/4" gap is important!
(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)
Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.
Setting the high and low needle valves properly:
NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle valve adjustment.
(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, waiting for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.
(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.
When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
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