Re: 1988 johnson spl
The primer solenoid allows fuel to be sent directly to the intake manifold to enrich the fuel/air mix for a cold start.
The red lever should be in line with the cylindrical solenoid base for normal operation, as seen in the thumbnail below.
The primer solenoid is operated by pushing the ignition key in while cranking, after squeezing the primer bulb to lift fuel into the fuel pump and carburetor bowls.
In emergencies, where a dead battery required manual starting, the lever could be moved 90 degrees, perpendicular to the cylinder. If left that way the engine would quickly flood.
The Schrader valve can be used for fogging oil when preparing for winterization or storage, and can also be used for your annual de-carbon treatment.