Trim Gage and Tachometer

[Givener316]

alright guys i have a two part question for you. I have a 1990 four winns 180 horizon w/ a 4.3 omc stern drive. i had the boat in for motor work last year and havent ran it since, and i pulled it out on the 3rd and noticed that the trim and tach doesnt work.<br />The tach doesnt even move but it has power to it. just not getting power from the motor. <br />The trim gage spikes all the way up when the key is turned.<br />wierd thing is that i notice two wires that are not hooked up. they are white and right by the coil and wired together like they hook on the same post. they are only long enough to go to the coil or someplace close. i hook them up to the coil and it kills the motor.<br /><br />my questions- what are the white wires for and how is the tach and trim gage wired?

 

[rattana]

Re: Trim Gage and Tachometer

If the wire is from the tach it should go to the negative post on the coil. For the tach you need +12VDC for power which you seem to have, and neg pulse from the coil to give RPM reading. That maybe the wire that is disconnected.

 

[Givener316]

Re: Trim Gage and Tachometer

the only wires that are on the back of the tach is the power wire and a ground and they are colored different from the wires that are hanging<br /><br />what would make the trim gage spike all the way up?<br /><br />is there suppose to be power to the wires going to the trim sending unit? i tested them and there is no power niether + or -. and what is the black box on the side of the esa the that wires from the sending unit go into for? <br /><br />could that go bad?

 

[Givener316]

Re: Trim Gage and Tachometer

how do you test a trim sending unit?

 

[MooseHootie]

Re: Trim Gage and Tachometer

The trim sensor is like a resistor. You check the resistance between the two wires when the drive is down and up the values should change. I just replaced mine a month ago. The tach should have a power wire,ground and a color wire that says sender on tach it would either come from the coil or the control module.

 

[Blk-n-Blu]

Re: Trim Gage and Tachometer

Givener, I believe the signal wire to the back of the tach is a gray wire.