Hello.<br />Last week I have installed a tach (0-6000rpm) from an 6 years old 4 cyl. Mercury on my 60HP Evinrude VRO from 1990.<br />The tach can be adjusted from 2 to 8 pol.<br />So since my Evinrude is 3 cyl. 2-stroke, I did adjust the tach to 6 pol.<br />So when I start up the motor, the tach was working fine, and was operation from 0-5500 rpm.<br />But this week the tach was working fine for about 30 min. From idle to apx. 3000 rpm, it works okay, but if the motor is running more than 3000 rpm, the tach is going down to apx. 1100 rpm.<br />And if I slow down again to apx. 3000 rpm, then the tach is jumping from 1100 to 3000 rpm. ????<br />Whats going on ??????????????????