1987 Johnson 90HP Tach Question

[etracer68]

I purchased a tach, to put on my 1987 90hp Johnson, Mod # J90TLCUR, I have the setting on 6p. When I turn the key on, it goes to 0, start the motor, and it reads about 800 rpm, (this is running the motor on muffs with no load). When I put in forword and rev up quickly, it seems it wont go past 3000 rpm. Also the volt gage does not read over 12.5 volts. I understand the tach reads from charging system. If it were not charging at all, would it still read? Why not going over 3000 rpm?

 

[petryshyn]

Re: 1987 Johnson 90HP Tach Question

Try it in the lake.....a quick rev on muffs is dangerous and inconclusive.....you may have charging system problems if the voltage doesn't climb past 12.5 while running. Check the system as per manual. I also have had bad tachs right out of the box. Verify the charging system first.