Tach Fluctuates on 2007 Merc 50 3-cyl 2 stroke

Molaker

Petty Officer 2nd Class
Joined
Jul 10, 2007
Messages
175
I've ordered a service manual for my Merc, but was hoping to resolve this problem before the manual will arrive.

My tach fluctuates roughly +/- 10-20%. It doesn't seem to make much difference what the RPM is - it happens anywhere between idle and WOT. I'm assuming the tach gets its input from the regulator, but I'm have a hard time establishing what wire it is on the motor. Can anyone point me in the right direction?
 
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