Tach ???

[chopper_man]

Hello everyone<br />I have done a search for answers to my tach question but found no answer.Here goes i have a 1978 bayliner mutiny with original gauges still in dash.I recently removed a dead 115 hp merc engine and put on a 1975 70hp(70ESL-75) johnson.Now i have located the gray wire in my control box to hook up the tach but will not work.There is no dial on the back to change setting to 6.I have looked in my Seloc manual but no answers to my problem.Could this mean i need to buy another tachometer?????Or am i completely overlooking something here??<br />Any help would be much appreciated.<br />Thanks Chopper

 

[chopper_man]

Re: Tach ???

Can anyone answer please before i dish out more money for a new tach??

 

[rickdb1boat]

Re: Tach ???

Did the Tach. work before with the Merc? Does the Tach. "Zero" when you turn the key to the on position? And is your new motors charging system working? It must work in order for the Tach. to work. You can check this with a voltmeter. Take voltage at the battery with the motor off. Then take it again with the motor running at fast idle (1500-2000 RPM's). See if there is a difference. Let us know on that first....

 

[chopper_man]

Re: Tach ???

Ok with motor off i got a reading of 11.24 volts,then at fast idle 14.8 volts so i assume the charging system is working??

 

[rickdb1boat]

Re: Tach ???

Did this Tach work with the other motor? Does it "Zero" when you turn the key to the on position?

 

[chopper_man]

Re: Tach ???

Yes it worked with 115 merc and it does zero when i turn the key on.

 

[rickdb1boat]

Re: Tach ???

If you know that the wiring is good and tight(Ground Especially) and you are getting power from the ignition (Which it appears to be doing), then the only 2 things it could be is that either it's not getting a signal off the gray wire(Possible broken wire between the motor and Tach.) or the Tach is bad. Try going directly to the yellow wire at the terminal block on the engine. You should see the gray wire back there that should be connected with a yellow/gray wire. Try the other yellow wire on the strip. If the tach works, rectifier is bad ( but we have pretty much ruled that out because it's charging). If not, Tach is bad or not compatable.

 

[chopper_man]

Re: Tach ???

Ok thanks Rick i will take a look tommorow and get back to you it's getting late.<br />Thanks again Chopper