"Quentin..... Your motor is in
"Quentin..... Your motor is indeed a 1954 5.5hp Johnson.
The fuel/oil ratio is 24/1 (1qt of 50/1 TCW-III oil to 6gal gas). A octane rating of 87 is fine.
The lower unit requires what is called "HiVis" (80/90w) gearlube which is available at Wal*Mart, K-Mart etc, and of course at any dealership.
If a philips screw exists in the lower unit skeg (the bottom fin), do not remove it as that screw would be a long shoulder bolt which is a pivot point for a internal shift lever.
If the engine has been sitting for quite some time, the carburetor will no doubt be gummed, fouled, clogged. In which case, it will require removing, cleaning, and rebuilding with a complete carburetor kit (possibly available at NAPA, and of course a OMC dealership).
I'd strongly suggest that you give the engine a strong test and run out before exposing your son to that fishing experience.
The proper carburetor adjusting procedure is as follows:
(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.
Joe (30+ Years With OMC)"