Please tell me what “Spark plug tube is” The ignation circuit seems to me to be no different than an automotive circuit, very basic with power, small wire to points & capacitor & one to the spark plug lead, from secondary winding. The others are safety control switches, choke & charging system. Pick one system at a time & research & repair before doing the next system. The rectificter seems very common to Mercury outboards, Honda Motorcycles & every else a bridge is used with 4 terminals ( don’t forget the bonding, grounding terminal. Both outputs generate 1/2 wave direct current, t’s very much the same as any outboard except the primary winding power comes from a battery supply & not using magnitism.
I assume the pink, orange brown terminals are part of the tachometer as sensing terminals as the othher two wires are the power supply + & = maybe a lamp for night use with a common bond or ground by mechinacial means. Not hard to understand taking one system at a time remembering they are totaly separt systems like Frank stated. just a different shape you may not be used to.Don’t be confused with “common” terminals linking the three systems to the power supply (battery) also. Again Frank has it correct, get the coils working fires. I had an outboard with a flakey bond th the ehgine block & one coil sent hi voltage to the other coil turning the points gold hot. You might trying bonding the magneto plate to the block as it turns when throttle is advanced & retarded. Dirty grease is a dielectric or insulator.
Good luck
