Tach and prop selection

[chuckee53]

good morning guys I have 2 questions ,I have a 83 johnson 150 and tach doesnt work I havent checked any wires yet but can you tell me which wire goes from the motor to the tach ,last owner changeg the motor so I dont even know if he hooked it up motor runs fine so i figure bad wiring or bad tach . also this 150 is on a 1980 18ft sterling (baja looking) runabout. it has a 14.5x19 alum. prop. it ran 50 mph with 2 people .I read you need to experiment with props and use size and pitch that runs best with motors high rpm range so my question is what is rpm range for an 83 J150 and any sugestion on prop pitch I wont know rpm till I get tach problem solved but Id hate to be doing 50 if I can be doing 60 thanks guys ,Chuck

 

[Boobie]

The gray wire goes to the tach, but get that working properly before you do any prop changing.