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Trim gauge reading is off 1979 100hp

H

HHP123

New member
My first post. I have a 1979 100hp Evinrude which runs great. The tilt motor was replaced awhile back, and sometime later I noticed that the trim gauge is reading erratic.

In the full down position it shows the needle above the max trim line range and as it is trimmed up it goes higher to the top. Where do I start looking for the remedy?

Thanks in advance for any help - advice offered.
 
Re: Trim gauge reading is off

what kind of gauges are they? (brand name)
is it the original gauge from motor?
 
Re: Trim gauge reading is off

OMC 10,

Thanks for the reply! No there is not an adjustment screw on the back. I see a resistor between the "I" and "S" terminals. With key on, trim all the way down I read 4+ volts between the "I" and "S" terminals and 12V+ with it tilted all the way up.

The "I" to "G" terminal reads 12V w/key on. The "S" to "G" follows the above readings, e.g. 4V - 12V through the tilt process.

Bad resistor?
 
Re: Trim gauge reading is off

jwbmarine,
Thanks for the lead. I just did a google search to no avail. Five of the Evinrude/Johnson Parts vendors all have the same online catalog. The power trim section didn't show the sending unit. Shows the gauge and every washer and O ring, but no sending unit.

Might you have a suggestion?
 
Re: Trim gauge reading is off

ok HHP on the back of mine there is a needle adjustment... didnt know if it was same sorry
 
Re: Trim gauge reading is off

Not sure if this applies.
My 75 model, the trim cylinder contains a resistor wire wrapped around a bobbin that travels with the piston.
In the cylinder body is a metal ball that bears against the bobbin and is connected to the S lead. As the engine trims, the bobbin slides past the ball the resistance changes.
The winding on the bobbing can come loose or shift positions and cause irratic resistance.
 
Re: Trim gauge reading is off

jwbmarine said:
0581754 sending unit assy. Power tilt & trim models only 1 $181.98
Click to expand...

jwbmarine,

Thank you for getting back to me. At that price I guess I will have to continue to listen to the changes in sound and turn around and look at the motor. :(
 
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