is trhis a tach or rectifier problem or ????

[phototom1]

1991 40 hp evinrude, model no. TE40ELEIA
I am have a issue either with the Tach or a possible rectifier or could it be something else.
1. When I start the motor the tach goes to 6000 at idle, volts read 12 after a few secs. the tach returns to 1000 still a little high for idle.
2. Idle up a touch tach goes to 1800 When I turn the motor off the tach hangs at 1000.
3. turn key to on position with out starting the motor the tach goes to 0.
4. Start motor tach goes to 1000, rev. motor up tach goes to 1600 most likely close to actual RPM's
throddle down tach goes to 1000.
5. Key off tach hangs at 1000
6. turn key on with out starting motor tach goes to 0.
7. Through out all of this the volts on the dash meter read 12 when key is on or motor is running.
Any help would be helpful.
Thanks in advance.
Tom H

 

[Will Bark]

Re: is trhis a tach or rectifier problem or ????

First, make sure all tach connections are clean and tight. Then measure vlotage of battery with engine off; start the engine on muffs or in water and measure voltage at battery, it should be higher than when you measured when "off". If it is higher then I would look at tach for a problem. Some tachs do bounce all over the place but seyyle down when engine is running. Good luck