Dad bought a 4 stroke Johnson 70. The factory tach would not work nor would the repair shops test tach. But an old mercury tach they had on hand did work. Any ideas why?????
Maybe the tach was bad in the first place...<br /><br />Maybe the repair shop tech doesn't know how to read, therefore he can't read the service manual in order to test the tach...<br /><br />-John
You would think it should be covered by warranty, but it doesn't appear we have the whole story...<br /><br />Ah, no - On the 40hp and larger Evinrude/Johnson 4-strokes, the tach signal is generated by the ECU, not the rectifier.<br /><br />-John
